Brown dwarf explained

Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main-sequence stars. Their mass is approximately 13 to 80 times that of Jupiter ^{[1] [2]} not big enough to sustain nuclear fusion of ordinary hydrogen (¹H) into helium in their cores, but massive enough to emit some light and heat from the fusion of deuterium (²H). The most massive ones (> ) can fuse lithium (⁷Li).

Astronomers classify self-luminous objects by spectral type, a distinction intimately tied to the surface temperature, and brown dwarfs occupy types M, L, T, and Y.^[3] As brown dwarfs do not undergo stable hydrogen fusion, they cool down over time, progressively passing through later spectral types as they age.

Their name comes not from the color of light they emit but from their falling between white dwarf stars and "dark" planets in size. To the naked eye, brown dwarfs would appear in different colors depending on their temperature. The warmest ones are possibly orange or red,^[4] while cooler brown dwarfs would likely appear magenta or black to the human eye.^[5] Brown dwarfs may be fully convective, with no layers or chemical differentiation by depth.^[6]

Though their existence was initially theorized in the 1960s, it was not until the mid-1990s that the first unambiguous brown dwarfs were discovered. As brown dwarfs have relatively low surface temperatures, they are not very bright at visible wavelengths, emitting most of their light in the infrared. However, with the advent of more capable infrared detecting devices, thousands of brown dwarfs have been identified. The nearest known brown dwarfs are located in the Luhman 16 system, a binary of L- and T-type brown dwarfs about 6.5lk=onNaNlk=on from the Sun. Luhman 16 is the third closest system to the Sun after Alpha Centauri and Barnard's Star.

History

Early theorizing

The objects now called "brown dwarfs" were theorized by Shiv S. Kumar in the 1960s to exist and were originally called black dwarfs,^[7] a classification for dark substellar objects floating freely in space that were not massive enough to sustain hydrogen fusion. However, (a) the term black dwarf was already in use to refer to a cold white dwarf; (b) red dwarfs fuse hydrogen; and (c) these objects may be luminous at visible wavelengths early in their lives. Because of this, alternative names for these objects were proposed, including planetar and substar. In 1975, Jill Tarter suggested the term "brown dwarf", using "brown" as an approximate color.^{[4] [8]}

The term "black dwarf" still refers to a white dwarf that has cooled to the point that it no longer emits significant amounts of light. However, the time required for even the lowest-mass white dwarf to cool to this temperature is calculated to be longer than the current age of the universe; hence such objects are expected to not yet exist.^[9]

Early theories concerning the nature of the lowest-mass stars and the hydrogen-burning limit suggested that a population I object with a mass less than 0.07 solar masses or a population II object less than would never go through normal stellar evolution and would become a completely degenerate star.^[10] The first self-consistent calculation of the hydrogen-burning minimum mass confirmed a value between 0.07 and 0.08 solar masses for population I objects.^[11]

Deuterium fusion

The discovery of deuterium burning down to and the impact of dust formation in the cool outer atmospheres of brown dwarfs in the late 1980s brought these theories into question. However, such objects were hard to find because they emit almost no visible light. Their strongest emissions are in the infrared (IR) spectrum, and ground-based IR detectors were too imprecise at that time to readily identify any brown dwarfs.

Since then, numerous searches by various methods have sought these objects. These methods included multi-color imaging surveys around field stars, imaging surveys for faint companions of main-sequence dwarfs and white dwarfs, surveys of young star clusters, and radial velocity monitoring for close companions.

GD 165B and class L

For many years, efforts to discover brown dwarfs were fruitless. In 1988, however, a faint companion to the white dwarf star GD 165 was found in an infrared search of white dwarfs. The spectrum of the companion GD 165B was very red and enigmatic, showing none of the features expected of a low-mass red dwarf. It became clear that GD 165B would need to be classified as a much cooler object than the latest M dwarfs then known. GD 165B remained unique for almost a decade until the advent of the Two Micron All-Sky Survey (2MASS) in 1997, which discovered many objects with similar colors and spectral features.

Today, GD 165B is recognized as the prototype of a class of objects now called "L dwarfs".^{[12] [13]}

Although the discovery of the coolest dwarf was highly significant at the time, it was debated whether GD 165B would be classified as a brown dwarf or simply a very-low-mass star, because observationally it is very difficult to distinguish between the two.

Soon after the discovery of GD 165B, other brown-dwarf candidates were reported. Most failed to live up to their candidacy, however, because the absence of lithium showed them to be stellar objects. True stars burn their lithium within a little over 100 Myr, whereas brown dwarfs (which can, confusingly, have temperatures and luminosities similar to true stars) will not. Hence, the detection of lithium in the atmosphere of an object older than 100 Myr ensures that it is a brown dwarf.

Gliese 229B and class T

The first class "T" brown dwarf was discovered in 1994 by Caltech astronomers Shrinivas Kulkarni, Tadashi Nakajima, Keith Matthews and Rebecca Oppenheimer,^[14] and Johns Hopkins scientists Samuel T. Durrance and David Golimowski. It was confirmed in 1995 as a substellar companion to Gliese 229. Gliese 229b is one of the first two instances of clear evidence for a brown dwarf, along with Teide 1. Confirmed in 1995, both were identified by the presence of the 670.8 nm lithium line. The latter was found to have a temperature and luminosity well below the stellar range.

Its near-infrared spectrum clearly exhibited a methane absorption band at 2 micrometres, a feature that had previously only been observed in the atmospheres of giant planets and that of Saturn's moon Titan. Methane absorption is not expected at any temperature of a main-sequence star. This discovery helped to establish yet another spectral class even cooler than L dwarfs, known as "T dwarfs", for which Gliese 229B is the prototype.

Teide 1 and class M

The first confirmed class "M" brown dwarf was discovered by Spanish astrophysicists Rafael Rebolo (head of the team), María Rosa Zapatero-Osorio, and Eduardo L. Martín in 1994.^[15] This object, found in the Pleiades open cluster, received the name Teide 1. The discovery article was submitted to Nature in May 1995, and published on 14 September 1995.^[16] Nature highlighted "Brown dwarfs discovered, official" on the front page of that issue.

Teide 1 was discovered in images collected by the IAC team on 6 January 1994 using the 80 cm telescope (IAC 80) at Teide Observatory, and its spectrum was first recorded in December 1994 using the 4.2 m William Herschel Telescope at Roque de los Muchachos Observatory (La Palma). The distance, chemical composition, and age of Teide 1 could be established because of its membership in the young Pleiades star cluster. Using the most advanced stellar and substellar evolution models at that moment, the team estimated for Teide 1 a mass of,^[17] which is below the stellar-mass limit. The object became a reference in subsequent young brown dwarf related works.

In theory, a brown dwarf below is unable to burn lithium by thermonuclear fusion at any time during its evolution. This fact is one of the lithium test principles used to judge the substellar nature of low-luminosity and low-surface-temperature astronomical bodies.

High-quality spectral data acquired by the Keck 1 telescope in November 1995 showed that Teide 1 still had the initial lithium abundance of the original molecular cloud from which Pleiades stars formed, proving the lack of thermonuclear fusion in its core. These observations confirmed that Teide 1 is a brown dwarf, as well as the efficiency of the spectroscopic lithium test.

For some time, Teide 1 was the smallest known object outside the Solar System that had been identified by direct observation. Since then, over 1,800 brown dwarfs have been identified, even some very close to Earth, like Epsilon Indi Ba and Bb, a pair of brown dwarfs gravitationally bound to a Sun-like star 12 light-years from the Sun,^[18] and Luhman 16, a binary system of brown dwarfs at 6.5 light-years from the Sun.

Theory

The standard mechanism for star birth is through the gravitational collapse of a cold interstellar cloud of gas and dust. As the cloud contracts, it heats due to the Kelvin–Helmholtz mechanism. Early in the process the contracting gas quickly radiates away much of the energy, allowing the collapse to continue. Eventually, the central region becomes sufficiently dense to trap radiation. Consequently, the central temperature and density of the collapsed cloud increase dramatically with time, slowing the contraction, until the conditions are hot and dense enough for thermonuclear reactions to occur in the core of the protostar. For a typical star, gas and radiation pressure generated by the thermonuclear fusion reactions within its core will support it against any further gravitational contraction. Hydrostatic equilibrium is reached, and the star will spend most of its lifetime fusing hydrogen into helium as a main-sequence star.

If, however, the initial mass of the protostar is less than about,^[19] normal hydrogen thermonuclear fusion reactions will not ignite in the core. Gravitational contraction does not heat the small protostar very effectively, and before the temperature in the core can increase enough to trigger fusion, the density reaches the point where electrons become closely packed enough to create quantum electron degeneracy pressure. According to the brown dwarf interior models, typical conditions in the core for density, temperature and pressure are expected to be the following:

10 g/cm ^{3} \lesssim \rho _{c} \lesssim 10 ^{3{g/{cm} ^{3} }} T _{c} \lesssim 3 x 10 ^{6K} P _{c} \sim 10 ^{5Mbar.} This means that the protostar is not massive or dense enough ever to reach the conditions needed to sustain hydrogen fusion. The infalling matter is prevented, by electron degeneracy pressure, from reaching the densities and pressures needed.

Further gravitational contraction is prevented and the result is a brown dwarf that simply cools off by radiating away its internal thermal energy. Note that, in principle, it is possible for a brown dwarf to slowly accrete mass above the hydrogen burning limit without initiating hydrogen fusion. This could happen via mass transfer in a binary brown dwarf system.

High-mass brown dwarfs versus low-mass stars

Lithium is generally present in brown dwarfs and not in low-mass stars. Stars, which reach the high temperature necessary for fusing hydrogen, rapidly deplete their lithium. Fusion of lithium-7 and a proton occurs, producing two helium-4 nuclei. The temperature necessary for this reaction is just below that necessary for hydrogen fusion. Convection in low-mass stars ensures that lithium in the whole volume of the star is eventually depleted. Therefore, the presence of the lithium spectral line in a candidate brown dwarf is a strong indicator that it is indeed a substellar object.

The lithium test

The use of lithium to distinguish candidate brown dwarfs from low-mass stars is commonly referred to as the lithium test, and was pioneered by Rafael Rebolo, Eduardo Martín and Antonio Magazzu. However, lithium is also seen in very young stars, which have not yet had enough time to burn it all.

Heavier stars, like the Sun, can also retain lithium in their outer layers, which never get hot enough to fuse lithium, and whose convective layer does not mix with the core where the lithium would be rapidly depleted. Those larger stars are easily distinguishable from brown dwarfs by their size and luminosity.

Conversely, brown dwarfs at the high end of their mass range can be hot enough to deplete their lithium when they are young. Dwarfs of mass greater than can burn their lithium by the time they are half a billion years old;^[20] thus the lithium test is not perfect.

Atmospheric methane

Unlike stars, older brown dwarfs are sometimes cool enough that, over very long periods of time, their atmospheres can gather observable quantities of methane, which cannot form in hotter objects. Dwarfs confirmed in this fashion include Gliese 229B.

Iron, silicate and sulfide clouds

Main-sequence stars cool, but eventually reach a minimum bolometric luminosity that they can sustain through steady fusion. This luminosity varies from star to star, but is generally at least 0.01% that of the Sun. Brown dwarfs cool and darken steadily over their lifetimes; sufficiently old brown dwarfs will be too faint to be detectable.Clouds are used to explain the weakening of the iron hydride (FeH) spectral line in late L-dwarfs. Iron clouds deplete FeH in the upper atmosphere, and the cloud layer blocks the view to lower layers still containing FeH. The later strengthening of this chemical compound at cooler temperatures of mid- to late T-dwarfs is explained by disturbed clouds that allows a telescope to look into the deeper layers of the atmosphere that still contains FeH.^[21] Young L/T-dwarfs (L2-T4) show high variability, which could be explained with clouds, hot spots, magnetically driven aurorae or thermochemical instabilities.^[22] The clouds of these brown dwarfs are explained as either iron clouds with varying thickness or a lower thick iron cloud layer and an upper silicate cloud layer. This upper silicate cloud layer can consist out of quartz, enstatite, corundum and/or fosterite.^{[23] [24]} It is however not clear if silicate clouds are always necessary for young objects.^[25] Silicate absorption can be directly observed in the mid-infrared at 8 to 12 μm. Observations with Spitzer IRS have shown that silicate absorption is common, but not ubiquitous, for L2-L8 dwarfs.^[26] Additionally, MIRI has observed silicate absorption in the planetary-mass companion VHS 1256b.^[27]

Iron rain as part of atmospheric convection processes is possible only in brown dwarfs, and not in small stars. The spectroscopy research into iron rain is still ongoing, but not all brown dwarfs will always have this atmospheric anomaly. In 2013, a heterogeneous iron-containing atmosphere was imaged around the B component in the nearby Luhman 16 system.^[28]

For late T-type brown dwarfs only a few variable searches were carried out. Thin cloud layers are predicted to form in late T-dwarfs from chromium and potassium chloride, as well as several sulfides. These sulfides are manganese sulfide, sodium sulfide and zinc sulfide.^[29] The variable T7 dwarf 2M0050–3322 is explained to have a top layer of potassium chloride clouds, a mid layer of sodium sulfide clouds and a lower layer of manganese sulfide clouds. Patchy clouds of the top two cloud layers could explain why the methane and water vapor bands are variable.^[30]

At the lowest temperatures of the Y-dwarf WISE 0855-0714 patchy cloud layers of sulfide and water ice clouds could cover 50% of the surface.^[31]

Low-mass brown dwarfs versus high-mass planets

Like stars, brown dwarfs form independently, but, unlike stars, they lack sufficient mass to "ignite" hydrogen fusion. Like all stars, they can occur singly or in close proximity to other stars. Some orbit stars and can, like planets, have eccentric orbits.

Size and fuel-burning ambiguities

Brown dwarfs are all roughly the same radius as Jupiter. At the high end of their mass range, the volume of a brown dwarf is governed primarily by electron-degeneracy pressure,^[32] as it is in white dwarfs; at the low end of the range, their volume is governed primarily by Coulomb pressure, as it is in planets. The net result is that the radii of brown dwarfs vary by only 10–15% over the range of possible masses. Moreover, the mass–radius relationship shows no change from about one Saturn mass to the onset of hydrogen burning, suggesting that from this perspective brown dwarfs are simply high-mass Jovian planets.^[33] This can make distinguishing them from planets difficult.

In addition, many brown dwarfs undergo no fusion; even those at the high end of the mass range (over) cool quickly enough that after 10 million years they no longer undergo fusion.

Heat spectrum

X-ray and infrared spectra are telltale signs of brown dwarfs. Some emit X-rays; and all "warm" dwarfs continue to glow tellingly in the red and infrared spectra until they cool to planet-like temperatures (under 1,000 K).

Gas giants have some of the characteristics of brown dwarfs. Like the Sun, Jupiter and Saturn are both made primarily of hydrogen and helium. Saturn is nearly as large as Jupiter, despite having only 30% the mass. Three of the giant planets in the Solar System (Jupiter, Saturn, and Neptune) emit much more (up to about twice) heat than they receive from the Sun.^{[34] [35]} All four giant planets have their own "planetary" systems, in the form of extensive moon systems.

Current IAU standard

Currently, the International Astronomical Union considers an object above (the limiting mass for thermonuclear fusion of deuterium) to be a brown dwarf, whereas an object under that mass (and orbiting a star or stellar remnant) is considered a planet. The minimum mass required to trigger sustained hydrogen burning (about) forms the upper limit of the definition.^{[2] [36]}

It is also debated whether brown dwarfs would be better defined by their formation process rather than by theoretical mass limits based on nuclear fusion reactions.^[37] Under this interpretation brown dwarfs are those objects that represent the lowest-mass products of the star formation process, while planets are objects formed in an accretion disk surrounding a star. The coolest free-floating objects discovered, such as WISE 0855, as well as the lowest-mass young objects known, like PSO J318.5−22, are thought to have masses below, and as a result are sometimes referred to as planetary-mass objects due to the ambiguity of whether they should be regarded as rogue planets or brown dwarfs. There are planetary-mass objects known to orbit brown dwarfs, such as 2M1207b, MOA-2007-BLG-192Lb, 2MASS J044144b and Oph 98 B.

The 13-Jupiter-mass cutoff is a rule of thumb rather than a quantity with precise physical significance. Larger objects will burn most of their deuterium and smaller ones will burn only a little, and the 13Jupiter-mass value is somewhere in between.^[38] The amount of deuterium burnt also depends to some extent on the composition of the object, specifically on the amount of helium and deuterium present and on the fraction of heavier elements, which determines the atmospheric opacity and thus the radiative cooling rate.^[39]

As of 2011 the Extrasolar Planets Encyclopaedia included objects up to 25 Jupiter masses, saying, "The fact that there is no special feature around in the observed mass spectrum reinforces the choice to forget this mass limit".^[40] As of 2016, this limit was increased to 60 Jupiter masses,^[41] based on a study of mass–density relationships.^[42]

The Exoplanet Data Explorer includes objects up to 24 Jupiter masses with the advisory: "The 13 Jupiter-mass distinction by the IAU Working Group is physically unmotivated for planets with rocky cores, and observationally problematic due to the sin i ambiguity."^[43] The NASA Exoplanet Archive includes objects with a mass (or minimum mass) equal to or less than 30 Jupiter masses.^[44]

Sub-brown dwarf

See main article: Sub-brown dwarf.

Objects below, called sub-brown dwarfs or planetary-mass brown dwarfs, form in the same manner as stars and brown dwarfs (i.e. through the collapse of a gas cloud) but have a mass below the limiting mass for thermonuclear fusion of deuterium.^[45]

Some researchers call them free-floating planets,^[46] whereas others call them planetary-mass brown dwarfs.^[47]

Role of other physical properties in the mass estimate

While spectroscopic features can help to distinguish between low-mass stars and brown dwarfs, it is often necessary to estimate the mass to come to a conclusion. The theory behind the mass estimate is that brown dwarfs with a similar mass form in a similar way and are hot when they form. Some have spectral types that are similar to low-mass stars, such as 2M1101AB. As they cool down the brown dwarfs should retain a range of luminosities depending on the mass.^[48] Without the age and luminosity, a mass estimate is difficult; for example, an L-type brown dwarf could be an old brown dwarf with a high mass (possibly a low-mass star) or a young brown dwarf with a very low mass. For Y dwarfs this is less of a problem, as they remain low-mass objects near the sub-brown dwarf limit, even for relatively high age estimates. For L and T dwarfs it is still useful to have an accurate age estimate. The luminosity is here the less concerning property, as this can be estimated from the spectral energy distribution.^[49] The age estimate can be done in two ways. Either the brown dwarf is young and still has spectral features that are associated with youth, or the brown dwarf co-moves with a star or stellar group (star cluster or association), where age estimates are easier to obtain. A very young brown dwarf that was further studied with this method is 2M1207 and the companion 2M1207b. Based on the location, proper motion and spectral signature, this object was determined to belong to the ~8-million-year-old TW Hydrae association, and the mass of the secondary was determined to be 8 ± 2, below the deuterium burning limit.^[50] An example of a very old age obtained by the co-movement method is the brown dwarf + white dwarf binary COCONUTS-1, with the white dwarf estimated to be billion years old. In this case the mass was not estimated with the derived age, but the co-movement provided an accurate distance estimate, using Gaia parallax. Using this measurement the authors estimated the radius, which was then used to estimate the mass for the brown dwarf as .^[51]

Observations

Classification of brown dwarfs

Spectral class M

These are brown dwarfs with a spectral class of M5.5 or later; they are also called late-M dwarfs. Some scientists regard them as red dwarfs. All brown dwarfs with spectral type M are young objects, such as Teide 1, which is the first M-type brown dwarf discovered, and LP 944-20, the closest M-type brown dwarf.

Spectral class L

The defining characteristic of spectral class M, the coolest type in the long-standing classical stellar sequence, is an optical spectrum dominated by absorption bands of titanium(II) oxide (TiO) and vanadium(II) oxide (VO) molecules. However, GD 165B, the cool companion to the white dwarf GD 165, had none of the hallmark TiO features of M dwarfs. The subsequent identification of many objects like GD 165B ultimately led to the definition of a new spectral class, the L dwarfs, defined in the red optical region of the spectrum not by metal-oxide absorption bands (TiO, VO), but by metal hydride emission bands (FeH, CrH, MgH, CaH) and prominent atomic lines of alkali metals (Na, K, Rb, Cs)., over 900 L dwarfs had been identified, most by wide-field surveys: the Two Micron All Sky Survey (2MASS), the Deep Near Infrared Survey of the Southern Sky (DENIS), and the Sloan Digital Sky Survey (SDSS). This spectral class also contains the coolest main-sequence stars (> 80 M_J), which have spectral classes L2 to L6.^[52]

Spectral class T

As GD 165B is the prototype of the L dwarfs, Gliese 229B is the prototype of a second new spectral class, the T dwarfs. T dwarfs are pinkish-magenta. Whereas near-infrared (NIR) spectra of L dwarfs show strong absorption bands of H₂O and carbon monoxide (CO), the NIR spectrum of Gliese 229B is dominated by absorption bands from methane (CH₄), a feature which in the Solar System is found only in the giant planets and Titan. CH₄, H₂O, and molecular hydrogen (H₂) collision-induced absorption (CIA) give Gliese 229B blue near-infrared colors. Its steeply sloped red optical spectrum also lacks the FeH and CrH bands that characterize L dwarfs and instead is influenced by exceptionally broad absorption features from the alkali metals Na and K. These differences led J. Davy Kirkpatrick to propose the T spectral class for objects exhibiting H- and K-band CH₄ absorption., 355 T dwarfs were known. NIR classification schemes for T dwarfs have recently been developed by Adam Burgasser and Tom Geballe. Theory suggests that L dwarfs are a mixture of very-low-mass stars and sub-stellar objects (brown dwarfs), whereas the T dwarf class is composed entirely of brown dwarfs. Because of the absorption of sodium and potassium in the green part of the spectrum of T dwarfs, the actual appearance of T dwarfs to human visual perception is estimated to be not brown, but magenta.^{[53] [54]} T-class brown dwarfs, such as WISE 0316+4307, have been detected more than 100 light-years from the Sun.

Spectral class Y

See also: List of Y-dwarfs.

In 2009, the coolest-known brown dwarfs had estimated effective temperatures between, and have been assigned the spectral class T9. Three examples are the brown dwarfs CFBDS J005910.90–011401.3, ULAS J133553.45+113005.2 and ULAS J003402.77−005206.7.^[55] The spectra of these objects have absorption peaks around 1.55 micrometres.^[55] Delorme et al. have suggested that this feature is due to absorption from ammonia and that this should be taken as indicating the T–Y transition, making these objects of type Y0.^{[55] [56]} However, the feature is difficult to distinguish from absorption by water and methane,^[55] and other authors have stated that the assignment of class Y0 is premature.

The first JWST spectral energy distribution of a Y-dwarf was able to observe several bands of molecules in the atmosphere of the Y0-dwarf WISE 0359−5401. The observations covered spectroscopy from 1 to 12 μm and photometry at 15, 18 and 21 μm. The molecules water (H₂O), methane (CH₄), carbon monoxide (CO), carbon dioxide (CO₂) and ammonia (NH₃) were detected in WISE 0359−5401. Many of these features have been observed before in this Y-dwarf and warmer T-dwarfs by other observatories, but JWST was able to observe them in a single spectrum. Methane is the main reservoir of carbon in the atmosphere of WISE 0359−5401, but there is still enough carbon left to form detectable carbon monoxide (at 4.5–5.0 μm) and carbon dioxide (at 4.2–4.35 μm) in the Y-dwarf. Ammonia was difficult to detect before JWST, as it blends in with the absorption feature of water in the near-infrared, as well at 5.5–7.1 μm. At longer wavelengths of 8.5–12 μm the spectrum of WISE 0359−5401 is dominated by the absorption of ammonia. At 3 μm there is an additional newly detected ammonia feature.^[57]

Colder lower atmosphere

Usually brown dwarfs have a pressure–temperature (P–T) profile in an adiabatic form, which means that the pressure and temperature increase with depth. JWST spectroscopy and photometry suggest that Y-dwarfs have P–T profiles that are not in the standard adiabatic form. This means that upper layers of the atmosphere have a warmer temperature and lower layers of the atmosphere have a colder temperature. This is explained with the rapid rotation of these isolated objects. The rapid rotation leads to dynamical, thermal, and chemical changes, which disrupt the convective transport of heat from the lower to the upper atmosphere. This different P–T profile influences the shape of the spectrum and influences the composition of carbon- and nitrogen-bearing molecules in the atmosphere of Y-dwarfs.^[58]

Individual Y-dwarf discoveries

Timeline of Y-dwarf discoveries:

• April 2010: Two newly discovered ultracool sub-brown dwarfs (UGPS 0722-05 and SDWFS 1433+35) were proposed as prototypes for spectral class Y0.^[59]
• February 2011: Luhman et al. reported the discovery of WD 0806−661 B, a brown dwarf companion to a nearby white dwarf, with a temperature of c.  and mass of .^[60] Though of planetary mass, Rodriguez et al. suggest it is unlikely to have formed in the same manner as planets.^[61]
• February 2011: Shortly after that, Liu et al. published an account of a "very cold" (c. ) brown dwarf orbiting another very-low-mass brown dwarf and noted, "Given its low luminosity, atypical colors and cold temperature, CFBDS J1458+10B is a promising candidate for the hypothesized Y spectral class."^[62]
• August 2011: Scientists using data from NASA's Wide-field Infrared Survey Explorer (WISE) discovered six objects that they classified as Y dwarfs with temperatures as cool as .^{[63] [64]} These were published in two papers.^{[65] [66]}

• July 2012: Seven new Y-dwarfs were discovered, making the total number of confirmed Y-dwarfs fourteen.^[67] One of the Y dwarfs, called WISE 1828+2650, was, as of August 2011, the record holder for the coldest brown dwarf—emitting no visible light at all, this type of object resembles a free-floating planet more than a star. WISE 1828+2650 was initially estimated to have an atmospheric temperature cooler than .^[68] Its temperature has since been revised, and newer estimates put it in the range of .^[69]
• November 2012: WISE J1639−6847 was discovered. As of February 2024, it was the second-closest known Y-dwarf to Earth.^[70]
• April 2014: WISE 0855−0714 was announced, with a temperature profile estimated around and a mass of .^[71] It was also unusual in that its observed parallax meant a distance close to light-years from the Solar System.
• May 2014: The Y-dwarf WISE J2209+2711 was published.^[72]
• November 2014: The object WISEA J1141−3326 was estimated to be a Y-dwarf^[73] and it was later confirmed.^[74]
• April 2015: The T+Y dwarf binary WISE J0146+4234 AB was discovered.^[75]
• May 2015: Three Y-dwarfs were discovered with Hubble, bringing the total number of confirmed Y-dwarfs to 21.^[76]
• June 2018: WISEA J0302−5817 was published as a Y-dwarf, and WISEA J1141−3326 was confirmed as a Y-dwarf.
• August 2019: A search of the CatWISE catalog revealed CWISEP J1935-1546, one of the coldest brown dwarfs with an estimated temperature of .^[77] In 2023 it was announced that CWISEP J1935-1546 had methane emission due to an aurora.^[78]
• January 2020: In January 2020 the discovery of WISE J0830+2837, initially discovered by citizen scientists of the Backyard Worlds project, was presented at the 235th meeting of the American Astronomical Society. This Y dwarf is 36.5 light-years distant from the Solar System and has a temperature of about .^[79]
• February 2020: The CatWISE catalog combined NASA's WISE and NEOWISE surveys.^[80] It expanded the number of faint sources and has therefore been used to find the faintest brown dwarfs, including Y dwarfs. Seventeen candidate Y dwarfs were discovered by the CatWISE researchers. Initial color with the Spitzer Space Telescope indicated that CW1446 is one of the reddest and coldest Y dwarfs.^[81] Additional data with Spitzer showed that CW1446 is the fifth-reddest brown dwarf, with a temperature of about and a distance of about 10 parsecs.^[82]
• August 2020: Five candidate Y-dwarfs were discovered via the Backyard Worlds project.
• April 2021: New Y-dwarf candidates were published by the CatWISE and Backyard Worlds teams in a collaborative paper.^[83]
• August 2021: Ross 19B, an old object near the T/Y-boundary orbiting an M-dwarf, was discovered by the Backyard Worlds team.^[84]
• April 2023: WISE J0336−0143 was confirmed as a Y-dwarf binary with JWST. The B secondary is likely one of the coldest confirmed Y-dwarfs as of December 2023, with an estimated temperature of .^[85]
• November 2023: CWISE J1055+5443, an object previously classified as a T-dwarf, was confirmed as a nearby Y-dwarf.^[86]
• December 2023: Three new Y-dwarf candidates were published. The total number of confirmed Y-dwarfs was 27, and 30 additional Y-dwarf candidates existed as of February 2024.
• January 2024: Two candidate planets orbiting white dwarfs were discovered with JWST. If spectroscopically confirmed they would likely be Y-dwarfs due to their cold estimated temperature (T_eff<200 K).^[87]

Role of vertical mixing

In the hydrogen-dominated atmosphere of brown dwarfs a chemical equilibrium between carbon monoxide and methane exists. Carbon monoxide reacts with hydrogen molecules and forms methane and hydroxyl in this reaction. The hydroxyl radical might later react with hydrogen and form water molecules. In the other direction of the reaction, methane reacts with hydroxyl and forms carbon monoxide and hydrogen. The chemical reaction is tilted towards carbon monoxide at higher temperatures (L-dwarfs) and lower pressure. At lower temperatures (T-dwarfs) and higher pressure the reaction is tilted towards methane, and methane predominates at the T/Y-boundary. However, vertical mixing of the atmosphere can cause methane to sink into lower layers of the atmosphere and carbon monoxide to rise from these lower and hotter layers. The carbon monoxide is slow to react back into methane because of an energy barrier that prevents the breakdown of the C-O bonds. This forces the observable atmosphere of a brown dwarf to be in a chemical disequilibrium. The L/T transition is mainly defined with the transition from a carbon-monoxide-dominated atmosphere in L-dwarfs to a methane-dominated atmosphere in T-dwarfs. The amount of vertical mixing can therefore push the L/T-transition to lower or higher temperatures. This becomes important for objects with modest surface gravity and extended atmospheres, such as giant exoplanets. This pushes the L/T transition to lower temperatures for giant exoplanets. For brown dwarfs this transition occurs at around 1200 K. The exoplanet HR 8799c, on the other hand, does not show any methane, while having a temperature of 1100K.

The transition between T- and Y-dwarfs is often defined as 500 K because of the lack of spectral observations of these cold and faint objects.^[88] Future observations with JWST and the ELTs might improve the sample of Y-dwarfs with observed spectra. Y-dwarfs are dominated by deep spectral features of methane, water vapor and possibly absorption features of ammonia and water ice. Vertical mixing, clouds, metallicity, photochemistry, lightning, impact shocks and metallic catalysts might influence the temperature at which the L/T and T/Y transition occurs.

Secondary features

Brown dwarf spectral types

Secondary features
pec	This suffix (e.g. L2pec) stands for "peculiar".^[89]
sd	This prefix (e.g. sdL0) stands for subdwarf and indicates a low metallicity and blue color^[90]
β	Objects with the beta (β) suffix (e.g. L4β) have an intermediate surface gravity.^[91]
γ	Objects with the gamma (γ) suffix (e.g. L5γ) have a low surface gravity.
red	The red suffix (e.g. L0red) indicates objects without signs of youth, but high dust content^[92]
blue	The blue suffix (e.g. L3blue) indicates unusual blue near-infrared colors for L dwarfs without obvious low metallicity^[93]

Young brown dwarfs have low surface gravities because they have larger radii and lower masses than the field stars of similar spectral type. These sources are noted by a letter beta (β) for intermediate surface gravity or gamma (γ) for low surface gravity. Indicators of low surface gravity include weak CaH, K I and Na I lines, as well as a strong VO line.^[91] Alpha (α) denotes normal surface gravity and is usually dropped. Sometimes an extremely low surface gravity is denoted by a delta (δ).^[93] The suffix "pec" stands for "peculiar"; this suffix is still used for other features that are unusual, and summarizes different properties, indicating low surface gravity, subdwarfs and unresolved binaries.^[94] The prefix sd stands for subdwarf and only includes cool subdwarfs. This prefix indicates a low metallicity and kinematic properties that are more similar to halo stars than to disk stars.^[90] Subdwarfs appear bluer than disk objects.^[95] The red suffix describes objects with red color, but an older age. This is not interpreted as low surface gravity, but as a high dust content.^{[92] [93]} The blue suffix describes objects with blue near-infrared colors that cannot be explained with low metallicity. Some are explained as L+T binaries, others are not binaries, such as 2MASS J11263991−5003550 and are explained with thin and/or large-grained clouds.^[93]

Spectral and atmospheric properties of brown dwarfs

The majority of flux emitted by L and T dwarfs is in the 1- to 2.5-micrometre near-infrared range. Low and decreasing temperatures through the late-M, -L, and -T dwarf sequence result in a rich near-infrared spectrum containing a wide variety of features, from relatively narrow lines of neutral atomic species to broad molecular bands, all of which have different dependencies on temperature, gravity, and metallicity. Furthermore, these low temperature conditions favor condensation out of the gas state and the formation of grains.Typical atmospheres of known brown dwarfs range in temperature from 2,200 down to .^[53] Compared to stars, which warm themselves with steady internal fusion, brown dwarfs cool quickly over time; more massive dwarfs cool more slowly than less massive ones. There is some evidence that the cooling of brown dwarfs slows down at the transition between spectral classes L and T (about 1000 K).^[96]

Observations of known brown dwarf candidates have revealed a pattern of brightening and dimming of infrared emissions that suggests relatively cool, opaque cloud patterns obscuring a hot interior that is stirred by extreme winds. The weather on such bodies is thought to be extremely strong, comparable to but far exceeding Jupiter's famous storms.

On January 8, 2013, astronomers using NASA's Hubble and Spitzer space telescopes probed the stormy atmosphere of a brown dwarf named 2MASS J22282889–4310262, creating the most detailed "weather map" of a brown dwarf thus far. It shows wind-driven, planet-sized clouds. The new research is a stepping stone toward a better understanding not only brown dwarfs, but also of the atmospheres of planets beyond the Solar System.^[97]

In April 2020 scientists reported clocking wind speeds of +650 ± 310 metres per second (up to 1,450 miles per hour) on the nearby brown dwarf 2MASS J10475385+2124234. To calculate the measurements, scientists compared the rotational movement of atmospheric features, as ascertained by brightness changes, against the electromagnetic rotation generated by the brown dwarf's interior. The results confirmed previous predictions that brown dwarfs would have high winds. Scientists are hopeful that this comparison method can be used to explore the atmospheric dynamics of other brown dwarfs and extrasolar planets.^[98]

Observational techniques

Coronagraphs have recently been used to detect faint objects orbiting bright visible stars, including Gliese 229B.

Sensitive telescopes equipped with charge-coupled devices (CCDs) have been used to search distant star clusters for faint objects, including Teide 1.

Wide-field searches have identified individual faint objects, such as Kelu-1 (30 light-years away).

Brown dwarfs are often discovered in surveys to discover exoplanets. Methods of detecting exoplanets work for brown dwarfs as well, although brown dwarfs are much easier to detect.

Brown dwarfs can be powerful emitters of radio emission due to their strong magnetic fields. Observing programs at the Arecibo Observatory and the Very Large Array have detected over a dozen such objects, which are also called ultracool dwarfs because they share common magnetic properties with other objects in this class.^[99] The detection of radio emission from brown dwarfs permits their magnetic field strengths to be measured directly.

Milestones

• 1995: First brown dwarf verified. Teide 1, an M8 object in the Pleiades cluster, is picked out with a CCD in the Spanish Observatory of Roque de los Muchachos of the Instituto de Astrofísica de Canarias.
• First methane brown dwarf verified. Gliese 229B is discovered orbiting red dwarf Gliese 229A (20 ly away) using an adaptive optics coronagraph to sharpen images from the 60inches reflecting telescope at Palomar Observatory on Southern California's Mount Palomar; follow-up infrared spectroscopy made with their 200inches Hale Telescope shows an abundance of methane.
• 1998: First X-ray-emitting brown dwarf found. Cha Helpha 1, an M8 object in the Chamaeleon I dark cloud, is determined to be an X-ray source, similar to convective late-type stars.
• 15 December 1999: First X-ray flare detected from a brown dwarf. A team at the University of California monitoring LP 944-20 (16 ly away) via the Chandra X-ray Observatory, catches a 2-hour flare.^[100]
• 27 July 2000: First radio emission (in flare and quiescence) detected from a brown dwarf. A team of students at the Very Large Array detected emission from LP 944–20.^[101]
• 30 April 2004: First detection of a candidate exoplanet around a brown dwarf: 2M1207b discovered with the VLT and the first directly imaged exoplanet.^[102]
• 20 March 2013: Discovery of the closest brown dwarf system: Luhman 16.^[103]
• 25 April 2014: Coldest-known brown dwarf discovered. WISE 0855−0714 is 7.2 light-years away (seventh-closest system to the Sun) and has a temperature between −48 and −13 °C.^[71]

Brown dwarf as an X-ray source

X-ray flares detected from brown dwarfs since 1999 suggest changing magnetic fields within them, similar to those in very-low-mass stars.

With no strong central nuclear energy source, the interior of a brown dwarf is in a rapid boiling, or convective state. When combined with the rapid rotation that most brown dwarfs exhibit, convection sets up conditions for the development of a strong, tangled magnetic field near the surface. The flare observed by Chandra from LP 944-20 could have its origin in the turbulent magnetized hot material beneath the brown dwarf's surface. A sub-surface flare could conduct heat to the atmosphere, allowing electric currents to flow and produce an X-ray flare, like a stroke of lightning. The absence of X-rays from LP 944-20 during the non-flaring period is also a significant result. It sets the lowest observational limit on steady X-ray power produced by a brown dwarf, and shows that coronas cease to exist as the surface temperature of a brown dwarf cools below about 2,800 K and becomes electrically neutral.

Using NASA's Chandra X-ray Observatory, scientists have detected X-rays from a low-mass brown dwarf in a multiple star system.^[104] This is the first time that a brown dwarf this close to its parent star(s) (Sun-like stars TWA 5A) has been resolved in X-rays.^[104] "Our Chandra data show that the X-rays originate from the brown dwarf's coronal plasma which is some 3 million degrees Celsius", said Yohko Tsuboi of Chuo University in Tokyo.^[104] "This brown dwarf is as bright as the Sun today in X-ray light, while it is fifty times less massive than the Sun", said Tsuboi.^[104] "This observation, thus, raises the possibility that even massive planets might emit X-rays by themselves during their youth!"^[104]

Brown dwarfs as radio sources

The first brown dwarf that was discovered to emit radio signals was LP 944-20, which was observed based on its X-ray emission. Approximately 5–10% of brown dwarfs appear to have strong magnetic fields and emit radio waves, and there may be as many as 40 magnetic brown dwarfs within 25 pc of the Sun based on Monte Carlo modeling and their average spatial density.^[105] The power of the radio emissions of brown dwarfs is roughly constant despite variations in their temperatures.^[99] Brown dwarfs may maintain magnetic fields of up to 6 kG in strength.^[106] Astronomers have estimated brown dwarf magnetospheres to span an altitude of approximately 10⁷ m given properties of their radio emissions.^[107] It is unknown whether the radio emissions from brown dwarfs more closely resemble those from planets or stars. Some brown dwarfs emit regular radio pulses, which are sometimes interpreted as radio emission beamed from the poles but may also be beamed from active regions. The regular, periodic reversal of radio wave orientation may indicate that brown dwarf magnetic fields periodically reverse polarity. These reversals may be the result of a brown dwarf magnetic activity cycle, similar to the solar cycle.^[108]

Recent developments

Estimates of brown dwarf populations in the solar neighbourhood suggest that there may be as many as six stars for every brown dwarf.^[109] A more recent estimate from 2017 using the young massive star cluster RCW 38 concluded that the Milky Way galaxy contains between 25 and 100 billion brown dwarfs.^[110] (Compare these numbers to the estimates of the number of stars in the Milky Way; 100 to 400 billion.)

In a study published in Aug 2017 NASA's Spitzer Space Telescope monitored infrared brightness variations in brown dwarfs caused by cloud cover of variable thickness. The observations revealed large-scale waves propagating in the atmospheres of brown dwarfs (similarly to the atmosphere of Neptune and other Solar System giant planets). These atmospheric waves modulate the thickness of the clouds and propagate with different velocities (probably due to differential rotation).^[111]

In August 2020, astronomers discovered 95 brown dwarfs near the Sun through the project Backyard Worlds: Planet 9.^[112]

In 2024 the James Webb Space Telescope provided the most detailed weather report yet on two brown dwarfs, revealing "stormy" conditions. These brown dwarfs, part of a Binary star system named WISE 1049AB discovered in 2013, are only 6.5 light-years away from Earth and are the closest brown dwarfs to our sun. Researchers discovered that they have turbulent clouds, likely made of silicate grains, with temperatures ranging from 875°C to 1026°C. This indicates that hot sand is being blown by winds on the brown dwarfs. Additionally, absorption signatures of carbon monoxide, methane, and water vapor were detected.^[113]

Binary brown dwarfs

Brown dwarf–brown dwarf binaries

Brown dwarfs binaries of type M, L, and T are less common with a lower mass of the primary.^[114] L-dwarfs have a binary fraction of about % and the binary fraction for late T, early Y-dwarfs (T5-Y0) is about 8±6%.^[115]

Brown dwarf binaries have a higher companion-to-host ratio

q = M _{B/M} _{A} for lower mass binaries. Binaries with a M-type star as a primary have for example a broad distribution of q with a preference of q≥0.4. Brown dwarfs on the other hand show a strong preference for q≥0.7. The separation is decreasing with mass: M-type stars have a separation peaking at 3–30 astronomical units (au), M-L-type brown dwarfs have a projected separation peaking at 5–8 au and T5–Y0 objects have a projected separation that follows a lognormal distribution with a peak separation of about 2.9 au.

An example is the closest brown dwarf binary Luhman 16 AB with a primary L7.5 dwarf and a separation of 3.5 au and q=0.85. The separation is on the lower end of the expected separation for M-L-type brown dwarfs, but the mass ratio is typical.

It is not known if the same trend continues with Y-dwarfs, because their sample size is so small. The Y+Y dwarf binaries should have a high mass ratio q and a low separation, reaching scales of less than one au.^[116] The Y+Y dwarf WISE J0336-0143 was recently confirmed as a binary with JWST and it has a mass ratio of q=0.62±0.05 and a separation of 0.97 astronomical units. The researchers point out that the sample size of low-mass binary brown dwarfs is too small to determine if WISE J0336-0143 is a typical representative of low-mass binaries or a peculiar system.^[117]

Observations of the orbit of binary systems containing brown dwarfs can be used to measure the mass of the brown dwarf. In the case of 2MASSW J0746425+2000321, the secondary weighs 6% of the solar mass. This measurement is called a dynamical mass.^{[118] [119]} The brown dwarf system closest to the Solar System is the binary Luhman 16. It was attempted to search for planets around this system with a similar method, but none were found.^[120]

Unusual brown dwarf binaries

The wide binary system 2M1101AB was the first binary with a separation greater than . The discovery of the system gave definitive insights to the formation of brown dwarfs. It was previously thought that wide binary brown dwarfs are not formed or at least are disrupted at ages of 1–10 Myr. The existence of this system is also inconsistent with the ejection hypothesis.^[121] The ejection hypothesis was a proposed hypothesis in which brown dwarfs form in a multiple system, but are ejected before they gain enough mass to burn hydrogen.^[122]

More recently the wide binary W2150AB was discovered. It has a similar mass ratio and binding energy as 2M1101AB, but a greater age and is located in a different region of the galaxy. While 2M1101AB is in a closely crowded region, the binary W2150AB is in a sparsely-separated field. It must have survived any dynamical interactions in its natal star cluster. The binary belongs also to a few L+T binaries that can be easily resolved by ground-based observatories. The other two are SDSS J1416+13AB and Luhman 16.^[123]

There are other interesting binary systems such as the eclipsing binary brown dwarf system 2MASS J05352184–0546085. Photometric studies of this system have revealed that the less massive brown dwarf in the system is hotter than its higher-mass companion.

Brown dwarfs around stars

See main article: Brown-dwarf desert. Brown dwarfs and massive planets in a close orbit (less than 5 au) around stars are rare and this is sometimes described as the brown dwarf desert. Less than 1% of stars with the mass of the sun have a brown dwarf within 3–5 au.^[124]

An example for a star–brown dwarf binary is the first discovered T-dwarf Gliese 229 B, which orbits around the main-sequence star Gliese 229 A, a red dwarf. Brown dwarfs orbiting subgiants are also known, such as TOI-1994b which orbits its star every 4.03 days.^[125]

There is also disagreement if some low-mass brown dwarfs should be considered planets. The NASA Exoplanet archive includes brown dwarfs with a minimum mass less or equal to 30 Jupiter masses as planets as long as there are other criteria fulfilled (e.g. orbiting a star).^[126] The Working Group on Extrasolar Planets (WGESP) of the IAU on the other hand only considers planets with a mass below 13 Jupiter masses.^[127]

White dwarf–brown dwarf binaries

Brown dwarfs around white dwarfs are quite rare. GD 165 B, the prototype of the L dwarfs, is one such system.^[128] Such systems can be useful in determining the age of the system and the mass of the brown dwarf. Other white dwarf-brown dwarf binaries are COCONUTS-1 AB (7 billion years old), and LSPM J0055+5948 AB (10 billion years old),^[129] SDSS J22255+0016 AB (2 billion years old)^[130] WD 0806−661 AB (1.5–2.7 billion years old).^[131]

Systems with close, tidally locked brown dwarfs orbiting around white dwarfs belong to the post common envelope binaries or PCEBs. Only eight confirmed PCEBs containing a white dwarf with a brown dwarf companion are known, including WD 0137-349 AB. In the past history of these close white dwarf–brown dwarf binaries, the brown dwarf is engulfed by the star in the red giant phase. Brown dwarfs with a mass lower than 20 Jupiter masses would evaporate during the engulfment.^{[132] [133]} The dearth of brown dwarfs orbiting close to white dwarfs can be compared with similar observations of brown dwarfs around main-sequence stars, described as the brown-dwarf desert.^{[134] [135]} The PCEB might evolve into a cataclysmic variable star (CV*) with the brown dwarf as the donor.^[136] Simulations have shown that highly evolved CV* are mostly associated with substellar donors (up to 80%).^[137] A type of CV*, called WZ Sge-type dwarf nova often show donors with a mass near the borderline of low-mass stars and brown dwarfs.^[138] The binary BW Sculptoris is such a dwarf nova with a brown dwarf donor. This brown dwarf likely formed when a donor star lost enough mass to become a brown dwarf. The mass loss comes with a loss of the orbital period until it reaches a minimum of 70–80 minutes at which the period increases again. This gives this evolutionary stage the name period bouncer. There could also exist brown dwarfs that merged with white dwarfs. The nova CK Vulpeculae might be a result of such a white dwarf–brown dwarf merger.^{[139] [140]}

Brown dwarfs around neutron stars

Substellar objects around neutron stars are known. An example are black widow pulsars, which are named after the original black widow pulsar PSR B1957+20. About 41 such black widows are known. A black widow pulsar is characterized by a millisecond pulsar with a substellar companion that is ablated by the strong stellar wind of the pulsar. If the companion has a mass below 0.1, it is called black widow, above this mass it is called redback pulsar.^[141]

Formation and evolution

Brown dwarfs form similarly to stars and are surrounded by protoplanetary disks,^[142] such as Cha 110913−773444. As of 2017 there is only one known proto-brown dwarf that is connected with a large Herbig–Haro object. This is the brown dwarf Mayrit 1701117, which is surrounded by a pseudo-disk and a Keplerian disk.^[143] Mayrit 1701117 launches the 0.7-light-year-long jet HH 1165, mostly seen in ionized sulfur.^{[144] [145]}

Disks around brown dwarfs have been found to have many of the same features as disks around stars; therefore, it is expected that there will be accretion-formed planets around brown dwarfs.^[142] Given the small mass of brown dwarf disks, most planets will be terrestrial planets rather than gas giants.^[146] If a giant planet orbits a brown dwarf across our line of sight, then, because they have approximately the same diameter, this would give a large signal for detection by transit.^[147] The accretion zone for planets around a brown dwarf is very close to the brown dwarf itself, so tidal forces would have a strong effect.^[146]

In 2020, the closest brown dwarf with an associated primordial disk - WISEA J120037.79-784508.3 (W1200-7845) - was discovered by the Disk Detective project when classification volunteers noted its infrared excess. It was vetted and analyzed by the science team who found that W1200-7845 had a 99.8% probability of being a member of the ε Chamaeleontis (ε Cha) young moving group association. Its parallax (using Gaia DR2 data) puts it at a distance of 102 parsecs (or 333 lightyears) from Earth - which is within the local Solar neighborhood.^{[148] [149]}

A paper from 2021 studied circumstellar discs around brown dwarfs in stellar associations that are a few million years old and 140 to 200 parsecs away. The researchers found that these disks are not massive enough to form planets in the future. There is evidence in these disks that might indicate that planet formation begins at earlier stages and that planets are already present in these disks. The evidence for disk evolution includes a decreasing disk mass over time, dust grain growth and dust settling.^[150] Disks around brown dwarfs usually have a radius smaller than 40 astronomical units, but three disks in the more distant Taurus molecular cloud have a radius larger than 70 au and were resolved with ALMA. These larger disks are able to form rocky planets with a mass >1 .^[151] There are also brown dwarfs with disks in associations older than a few million years,^[152] which might be evidence that disks around brown dwarfs need more time to dissipate. Especially old disks (>20 Myrs) are sometimes called Peter Pan disks. Currently 2MASS J02265658-5327032 is the only known brown dwarf that has a Peter Pan disk.^[153]

The brown dwarf Cha 110913−773444, located 500 light-years away in the constellation Chamaeleon, may be in the process of forming a miniature planetary system. Astronomers from Pennsylvania State University have detected what they believe to be a disk of gas and dust similar to the one hypothesized to have formed the Solar System. Cha 110913−773444 is the smallest brown dwarf found to date, and if it formed a planetary system, it would be the smallest-known object to have one.^[154]

Planets around brown dwarfs

According to the IAU working definition (from August 2018) an exoplanet can orbit a brown dwarf. It requires a mass below 13 and a mass ratio of M/M_central<2/(25+√621). This means that an object with a mass up to 3.2 around a brown dwarf with a mass of 80 is considered a planet. It also means that an object with a mass up to 0.52 around a brown dwarf with a mass of 13 is considered a planet.^[155]

The super-Jupiter planetary-mass objects 2M1207b, 2MASS J044144 and Oph 98 B that are orbiting brown dwarfs at large orbital distances may have formed by cloud collapse rather than accretion and so may be sub-brown dwarfs rather than planets, which is inferred from relatively large masses and large orbits. The first discovery of a low-mass companion orbiting a brown dwarf (ChaHα8) at a small orbital distance using the radial velocity technique paved the way for the detection of planets around brown dwarfs on orbits of a few AU or smaller.^{[156] [157]} However, with a mass ratio between the companion and primary in ChaHα8 of about 0.3, this system rather resembles a binary star. Then, in 2008, the first planetary-mass companion in a relatively small orbit (MOA-2007-BLG-192Lb) was discovered orbiting a brown dwarf.^[158]

Planets around brown dwarfs are likely to be carbon planets depleted of water.^[159]

A 2017 study, based upon observations with Spitzer estimates that 175 brown dwarfs need to be monitored in order to guarantee (95%) at least one detection of a below earth-sized planet via the transiting method.^[160] JWST could potentially detect smaller planets. The orbits of planets and moons in the solar system often align with the orientation of the host star/planet they orbit. Assuming the orbit of a planet is aligned with the rotational axis of a brown dwarf or planetary-mass object, the geometric transit probability of an object similar to Io can be calculated with the formula cos(79.5°)/cos(inclination).^[161] The inclination was estimated for several brown dwarfs and planetary-mass objects. SIMP 0136 for example has an estimated inclination of 80°±12.^[162] Assuming the lower bound of i≥68° for SIMP 0136, this results in a transit probability of ≥48.6% for close-in planets. It is however not known how common close-in planets are around brown dwarfs and they might be more common for lower-mass objects, as disk sizes seem to decrease with mass.

Habitability

Habitability for hypothetical planets orbiting brown dwarfs has been studied. Computer models suggesting conditions for these bodies to have habitable planets are very stringent, the habitable zone being narrow, close (T dwarf 0.005 AU) and decreasing with time, due to the cooling of the brown dwarf (they fuse for at most 10 million years). The orbits there would have to be of extremely low eccentricity (on the order of 10 to the minus 6) to avoid strong tidal forces that would trigger a runaway greenhouse effect on the planets, rendering them uninhabitable. There would also be no moons.^[163]

Superlative brown dwarfs

See main article: List of brown dwarfs. In 1984, it was postulated by some astronomers that the Sun may be orbited by an undetected brown dwarf (sometimes referred to as Nemesis) that could interact with the Oort cloud just as passing stars can. However, this hypothesis has fallen out of favor.^[164]

Table of firsts

Record	Name	Spectral type	RA/Dec	Constellation	Notes
First discovered	[Gliese 569 Bab]] (Companions of M3 field star)	M8.5 and M9	14^h54^m29.2^s +16°06'04"	Bootes	Imaged in 1985 published in 1988 weighed in 2004
First imaged with coronography	Gliese 229 B	T6.5	06^h10^m34.62^s −21°51'52.1"	Lepus	Discovered 1994
First with planemo	2M1207	M8	12^h07^m33.47^s −39°32'54.0"	Centaurus	Planet discovered in 2004
First with a circumstellar disk	ChaHα1	M7.5	11^h07^m17.0^s −77°35'54"	Chamaeleon	Disk discovered in 2000, first disk around a bona fide brown dwarf, also first x-ray emitting^[165]
First with bipolar outflow	Rho-Oph 102 (SIMBAD: [GY92] 102)		16 26 42.758 −24 41 22.24	Ophiuchus	partly resolved outflow^[166]
First with large-scale Herbig-Haro object	Mayrit 1701117 (Herbig-Haro object: HH 1165)	proto-BD	05 40 25.799 −02 48 55.42	Orion	projected length of the Herbig-Haro object: 0.8 light-years (0.26 pc)
First field type (solitary)	Teide 1	M8	3^h47^m18.0^s +24°22'31"	Taurus	1995
First as a companion to a normal star	Gliese 229 B	T6.5	06^h10^m34.62^s −21°51'52.1"	Lepus	1995
First spectroscopic binary brown dwarf	PPL 15 A, B^[167]	M6.5	03^h 48^m 4.659^s +23° 39' 30.32″	Taurus	Basri and Martín 1999
First eclipsing binary brown dwarf	2M0535-05^[168]	M6.5		Orion	Stassun 2006, 2007 (distance ~450 pc)
First binary brown dwarf of T Type	Epsilon Indi Ba, Bb^[169]	T1 + T6	22^h 03^m 21.65363^s −56° 47′ 09.5228″	Indus	Distance: 3.626pc
First binary brown dwarf of Y Type	WISE J0336−0143	Y+Y	03^h 36^m 05.052^s −01° 43′ 50.48″	Eridanus	2023
First trinary brown dwarf	DENIS-P J020529.0-115925 A/B/C	L5, L8 and T0	02^h05^m29.40^s −11°59'29.7"	Cetus	Delfosse et al. 1997^[170]
First halo brown dwarf	2MASS J05325346+8246465	sdL7	05^h32^m53.46^s +82°46'46.5"	Gemini	Burgasser et al. 2003^[171]
First with late-M spectrum	Teide 1	M8	3^h47^m18.0^s +24°22'31"	Taurus	1995
First with L spectrum	GD 165B	L4		Boötes	1988
First with T spectrum	Gliese 229 B	T6.5	06^h10^m34.62^s −21°51'52.1"	Lepus	1995
Latest-T spectrum	ULAS J003402.77−005206.7	T9^[172]		Cetus	2007
First with Y spectrum	CFBDS0059	~Y0		Cetus	2008; this is also classified as a T9 dwarf, due to its close resemblance to other T dwarfs.
First X-ray-emitting	ChaHα1	M8		Chamaeleon	1998
First X-ray flare	LP 944–20	M9V	03^h39^m35.22^s −35°25'44.1"	Fornax	1999
First radio emission (in flare and quiescence)	LP 944-20	M9V	03^h39^m35.22^s −35°25'44.1"	Fornax	2000
First potential brown dwarf auroras discovered	LSR J1835+3259	M8.5		Lyra	2015
First detection of differential rotation in a brown dwarf	TVLM 513-46546	M9	15^h01^m08.3^s +22°50'02"	Boötes	Equator rotates faster than poles by 0.022 radians / day^[173]
First confirmed brown dwarf to have survived the primary's red giant phase	WD 0137−349 B^[174]	L8		Sculptor (constellation)

Table of extremes

Record	Name	Spectral type	RA/Dec	Constellation	Notes
Oldest	LSPM J0055+5948 B Wolf 1130 C	T8 sdT8 L8	or or	Cassiopeia, Cygnus or Pictor	three of the few examples with a good age estimate: LSPM J0055B: 10±3 billion years Wolf 1130C: >10 billion years^[175] CWISE J0602-4624: billion years^[176]
Youngest	2MASS J05413280-0151272	M8.5		Orion	One brown dwarf member of the about 0.5 Myr-old Flame Nebula. object^[177]
Most massive	SDSS J010448.46+153501.8^[178]	usdL1.5	01^h04^m48.46^s +15°35'01.8"	Pisces	distance is ~180–290 pc, mass is ~. Transitional brown dwarfs.
Metal-rich
Metal-poor	SDSS J010448.46+153501.8	usdL1.5	01^h04^m48.46^s +15°35'01.8"	Pisces	distance is ~180–290 pc, metallicity is ~0.004 ZSol. Transitional brown dwarfs.
Least massive
Largest
Smallest	WISEA 1810−1010	esdT		Serpens	Radius is (~92,400 km)^[179]
Fastest rotating	2MASS J03480772−6022270	T7	03^h48^m07.72^s –60°22'27.1"	Reticulum	Rotational period of hours^[180]
Farthest	KMT-2016-BLG-2142 b			Sagittarius	(microlensing)^[181] has a distance of 5,850 to 8,020 parsec. Could also be massive gas giant.^[182]
Nearest	Luhman 16 AB	L7.5 + T0.5 ± 1		Vela	Distance: ~6.5 ly
Brightest	LP 944-20	opt: M9beta,IR: L0:		Fornax	According to the ultracool fundamental properties^[183] this object shows signs of youth and could therefore be a brown dwarf with 19.85±13.02 and JMKO=10.68±0.03 mag
Dimmest	L 97-3B	Y1		Volans	jmag=25.42, planetary-mass object
Hottest
Coolest	WISE 0855−0714	Y4		Hydra	Temperature:
Coolest radio-flaring	WISE J062309.94-045624.6	T8	06^h23^m09.28^s −04°56'22.8"	Monoceros	brown dwarf with 4.17 mJy bursts^[184]
Most dense	TOI-569b^[185]		07^h 40^m 24.658^s −42° 09′ 16.74″	Puppis	Transiting, has with a diameter 0.79 ± 0.02 times that of Jupiter. Density is 171.3g/cm^3.
Least dense

See also

• Fusor (astronomy)
  • • • • Stellification
• WD 0032-317 b
• List of brown dwarfs
• List of Y-dwarfs

External links

• HubbleSite newscenter – Weather patterns on a brown dwarf
• Allard . France . Homeier . Derek . 2007 . Brown dwarfs . . 2 . 12 . 4475 . 10.4249/scholarpedia.4475 . 2007SchpJ...2.4475A . free .

History

• Kumar, Shiv S.; Low-Luminosity Stars. Gordon and Breach, London, 1969—an early overview paper on brown dwarfs
• The Columbia Encyclopedia: "Brown Dwarfs"

Details

• A current list of L and T dwarfs
• A geological definition of brown dwarfs, contrasted with stars and planets (via Berkeley)
• I. Neill Reid's pages at the Space Telescope Science Institute:
  • On spectral analysis of M dwarfs, L dwarfs, and T dwarfs
  • Temperature and mass characteristics of low-temperature dwarfs
• First X-ray from brown dwarf observed, Spaceref.com, 2000
• Montes, David; "Brown Dwarfs and ultracool dwarfs (late-M, L, T)", UCM
• Wild Weather: Iron Rain on Failed Stars—scientists are investigating astonishing weather patterns on brown dwarfs, Space.com, 2006
• NASA Brown dwarf detectives —Detailed information in a simplified sense
• Brown Dwarfs—Website with general information about brown dwarfs (has many detailed and colorful artist's impressions)

Stars

• Cha Halpha 1 stats and history
• "A census of observed brown dwarfs" (not all confirmed), 1998
• Luhman . Kevin L. . Adame . Lucía . d'Alessio . Paola . Calvet . Nuria . Hartmann . Lee . Megeath . S. Thomas . Fazio . Giovanni G. . 2005 . Discovery of a Planetary-Mass Brown Dwarf with a Circumstellar Disk . The Astrophysical Journal . 635 . 1 . L93–L96 . astro-ph/0511807 . 2005ApJ...635L..93L . 10.1086/498868 . 11685964 .
• Michaud, Peter; Heyer, Inge; Leggett, Sandy K.; and Adamson, Andy; "Discovery Narrows the Gap Between Planets and Brown Dwarfs", Gemini and Joint Astronomy Centre, 2007
• Deacon, Niall R.; and Hambly, Nigel C.; "Y-Spectral class for Ultra-Cool Dwarfs", 2006

Notes and References

1. Web site: Boss . Alan . McDowell . Tina . April 3, 2001 . Are They Planets or What? . dead . https://web.archive.org/web/20060928065124/http://www.carnegieinstitution.org/News4-3%2C2001.html . September 28, 2006 . March 31, 2022 . Untitled Document . Carnegie Institution of Washington.
2. News: Wethington . Nicholos . October 6, 2008 . Dense Exoplanet Creates Classification Calamity . . March 31, 2022.
3. Book: Springer, Cham . 50 Years of Brown Dwarfs . SpringerLink . 2014 . 978-3-319-01162-2 . Joergens . Viki . Astrophysics and Space Science Library . 401 . XI, 168 . 10.1007/978-3-319-01162-2 . 2214-7985 . 0067-0057 . March 31, 2022 . subscription.
4. Web site: Cain . Fraser . January 6, 2009 . If Brown Isn't a Color, What Color are Brown Dwarfs? . 24 September 2013.
5. Burrows . Adam . Adam Burrows . Hubbard . William B. . Lunine . Jonathan I. . Jonathan Lunine . Liebert . James . 2001 . The Theory of Brown Dwarfs and Extrasolar Giant Planets . Reviews of Modern Physics . 73 . 3 . 719–765 . astro-ph/0103383 . 2001RvMP...73..719B . 10.1103/RevModPhys.73.719 . 204927572.
6. Web site: O'Neill . Ian . 13 September 2011 . Violent Storms Rage on Nearby Brown Dwarf . Seeker.com.
7. Kumar . Shiv S. . Study of Degeneracy in Very Light Stars . Astronomical Journal . 67 . 579 . 1962 . 10.1086/108658 . 1962AJ.....67S.579K. free .
8. Book: Croswell . Ken . Planet Quest: The Epic Discovery of Alien Solar Systems . 1999 . Oxford University Press . 978-0-192-88083-3 . 118–119 .
9. Web site: April 10, 2020 . When will the Sun become a black dwarf? . 2022-05-02 . Astronomy.com . en.
10. Kumar . Shiv S. . 1963 . The Structure of Stars of Very Low Mass . Astrophysical Journal . 137 . 1121 . 1963ApJ...137.1121K . 10.1086/147589 .
11. Hayashi . Chushiro . Chushiro Hayashi . Nakano . Takenori . 1963 . Evolution of Stars of Small Masses in the Pre-Main-Sequence Stages . Progress of Theoretical Physics . 30 . 460–474 . 1963PThPh..30..460H . 10.1143/PTP.30.460 . 4 . free .
12. Martín . Eduardo L. . Basri . Gibor . Gibor Basri . Delfosse . Xavier . Forveille . Thierry . Keck HIRES spectra of the brown dwarf DENIS-P J1228.2-1547 . . 327 . L29–L32 . 1997 . 1997A&A...327L..29M.
13. Kirkpatrick . J. Davy . J. Davy Kirkpatrick . Reid . I. Neill . Liebert . James . Cutri . Roc M. . Nelson . Brant . Beichmann . Charles A. . Charles A. Beichman . Dahn . Conard C. . Monet . David G. . Gizis . John E. . Skrutskie . Michael F. . Dwarfs Cooler than M: The Definition of Spectral Type L Using Discoveries from the 2 Micron All-Sky Survey (2MASS) . The Astrophysical Journal . 519 . 2 . 802–833 . 1999 . 10.1086/307414 . 1999ApJ...519..802K . 73569208 .
14. Web site: Astronomers Announce First Clear Evidence of a Brown Dwarf . STScI . en . 2019-10-23 .
15. Web site: Instituto de Astrofísica de Canarias, IAC . Iac.es . 2013-03-16 .
16. Discovery of a brown dwarf in the Pleiades star cluster . en . Rebolo . Rafael . Rafael Rebolo . Zapatero-Osorio . María Rosa . Martín . Eduardo L. . Nature . 377 . 6545 . September 1995 . 129–131 . 1995Natur.377..129R . 10.1038/377129a0 . 28029538 .
17. Leech . Kieron . Altieri . Bruno . Metcalfe . Liam . Martin . Eduardo L. . Rebolo . Rafael . Rafael Rebolo . Zapatero-Osorio . María Rosa . Laureijs . René J. . Prusti . Timo . Salama . Alberto . Siebenmorgen . Ralf . Claes . Peter . Trams . Norman . 2000 . Mid-IR Observations of the Pleiades Brown Dwarfs Teide 1 & Calar 3 . ASP Conference Series . 212 . 82–87 . 2000ASPC..212...82L .
18. Epsilon Indi Ba/Bb: the nearest binary brown dwarf . Mark J. . McCaughrean . Laird M. . Close . Ralf-Dieter . Scholz . Rainer . Lenzen . Beth A. . Biller . Wolfgang . Brandner . Markus . Hartung . Nicolas . Lodieu . Astronomy & Astrophysics . 413 . 3 . January 2004 . 1029–1036 . 10.1051/0004-6361:20034292 . astro-ph/0309256. 15407249 .
19. The theory of brown dwarfs and extrasolar giant planets . Burrows . Adam . Hubbard . W. B. . Lunine . J. I. . Liebert . James . Reviews of Modern Physics . 73 . 3 . 719–765 . July 2001 . 10.1103/RevModPhys.73.719 . astro-ph/0103383 . 2001RvMP...73..719B . 204927572 . Hence the HBMM at solar metallicity and Y_α = 50.25 is 0.07 – 0.074, ... while the HBMM at zero metallicity is 0.092 .
20. Kulkarni . Shrinivas R. . Shrinivas Kulkarni . Brown Dwarfs: A Possible Missing Link Between Stars and Planets . Science . 30 May 1997 . 276 . 5317 . 1350–1354 . 10.1126/science.276.5317.1350 . 1997Sci...276.1350K .
21. Burgasser . Adam J. . Marley . Mark S. . Ackerman . Andrew S. . Saumon . Didier . Lodders . Katharina . Dahn . Conard C. . Harris . Hugh C. . Kirkpatrick . J. Davy . 2002-06-01 . Evidence of Cloud Disruption in the L/T Dwarf Transition . The Astrophysical Journal . 571 . 2 . L151–L154 . 10.1086/341343 . astro-ph/0205051 . 2002ApJ...571L.151B . 0004-637X. free .
22. Vos . Johanna M. . Faherty . Jacqueline K. . Gagné . Jonathan . Marley . Mark . Metchev . Stanimir . Gizis . John . Rice . Emily L. . Cruz . Kelle . 2022-01-01 . Let the Great World Spin: Revealing the Stormy, Turbulent Nature of Young Giant Exoplanet Analogs with the Spitzer Space Telescope . The Astrophysical Journal . 924 . 2 . 68 . 10.3847/1538-4357/ac4502 . 2201.04711 . 2022ApJ...924...68V . 0004-637X. free .
23. Vos . Johanna M. . Burningham . Ben . Faherty . Jacqueline K. . Alejandro . Sherelyn . Gonzales . Eileen . Calamari . Emily . Bardalez Gagliuffi . Daniella . Visscher . Channon . Tan . Xianyu . Morley . Caroline V. . Marley . Mark . Gemma . Marina E. . Whiteford . Niall . Gaarn . Josefine . Park . Grace . 2023-02-01 . Patchy Forsterite Clouds in the Atmospheres of Two Highly Variable Exoplanet Analogs . The Astrophysical Journal . 944 . 2 . 138 . 10.3847/1538-4357/acab58 . 2212.07399 . 2023ApJ...944..138V . 0004-637X. free .
24. Manjavacas . Elena . Karalidi . Theodora . Vos . Johanna M. . Biller . Beth A. . Lew . Ben W. P. . 2021-11-01 . Revealing the Vertical Cloud Structure of a Young Low-mass Brown Dwarf, an Analog to the β-Pictoris b Directly Imaged Exoplanet, through Keck I/MOSFIRE Spectrophotometric Variability . The Astronomical Journal . 162 . 5 . 179 . 10.3847/1538-3881/ac174c . 2107.12368 . 2021AJ....162..179M . 0004-6256. free .
25. Tremblin . P. . Chabrier . G. . Baraffe . I. . Liu . Michael. C. . Magnier . E. A. . Lagage . P. -O. . Alves de Oliveira . C. . Burgasser . A. J. . Amundsen . D. S. . Drummond . B. . 2017-11-01 . Cloudless Atmospheres for Young Low-gravity Substellar Objects . The Astrophysical Journal . 850 . 1 . 46 . 10.3847/1538-4357/aa9214 . 1710.02640 . 2017ApJ...850...46T . 0004-637X. free .
26. Suárez . Genaro . Metchev . Stanimir . 2022-07-01 . Ultracool dwarfs observed with the Spitzer infrared spectrograph - II. Emergence and sedimentation of silicate clouds in L dwarfs, and analysis of the full M5-T9 field dwarf spectroscopic sample . Monthly Notices of the Royal Astronomical Society . 513 . 4 . 5701–5726 . 10.1093/mnras/stac1205 . free . 0035-8711. 2205.00168 . 2022MNRAS.513.5701S .
27. Miles . Brittany E. . Biller . Beth A. . Patapis . Polychronis . Worthen . Kadin . Rickman . Emily . Hoch . Kielan K. W. . Skemer . Andrew . Perrin . Marshall D. . Whiteford . Niall . Chen . Christine H. . Sargent . B. . Mukherjee . Sagnick . Morley . Caroline V. . Moran . Sarah E. . Bonnefoy . Mickael . 2023-03-01 . The JWST Early-release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 μm Spectrum of the Planetary-mass Companion VHS 1256-1257 b . The Astrophysical Journal . 946 . 1 . L6 . 10.3847/2041-8213/acb04a . 2209.00620 . 2023ApJ...946L...6M . 0004-637X. free .
28. Biller . Beth A. . Crossfield . Ian J. M. . Mancini . Luigi . Ciceri . Simona . Southworth . John . Kopytova . Taisiya G. . Bonnefoy . Mickaël . Deacon . Niall R. . Schlieder . Joshua E. . Buenzli . Esther . Brandner . Wolfgang . Allard . France . Homeier . Derek . Freytag . Bernd . Bailer-Jones . Coryn A. L. . Greiner . Jochen . Henning . Thomas . Goldman . Bertrand . Weather on the Nearest Brown Dwarfs: Resolved Simultaneous Multi-Wavelength Variability Monitoring of WISE J104915.57–531906.1AB . . 6 November 2013 . 778. 1 . L10 . 10.1088/2041-8205/778/1/l10 . 1310.5144 . 2013ApJ...778L..10B . 56107487 .
29. Morley . Caroline V. . Fortney . Jonathan J. . Marley . Mark S. . Visscher . Channon . Saumon . Didier . Leggett . S. K. . 2012-09-01 . Neglected Clouds in T and Y Dwarf Atmospheres . The Astrophysical Journal . 756 . 2 . 172 . 10.1088/0004-637X/756/2/172 . 0004-637X. 1206.4313 . 2012ApJ...756..172M . 118398946 .
30. Manjavacas . Elena . Karalidi . Theodora . Tan . Xianyu . Vos . Johanna M. . Lew . Ben W. P. . Biller . Beth A. . Oliveros-Gómez . Natalia . 2022-08-01 . Top-of-the-atmosphere and Vertical Cloud Structure of a Fast-rotating Late T Dwarf . The Astronomical Journal . 164 . 2 . 65 . 10.3847/1538-3881/ac7953 . 2206.07566 . 2022AJ....164...65M . 0004-6256. free .
31. Faherty . Jacqueline K. . Tinney . C. G. . Skemer . Andrew . Monson . Andrew J. . 2014-09-01 . Indications of Water Clouds in the Coldest Known Brown Dwarf . The Astrophysical Journal . 793 . 1 . L16 . 10.1088/2041-8205/793/1/L16 . 0004-637X. 1408.4671 . 2014ApJ...793L..16F . 119246100 .
32. Planetesimals to Brown Dwarfs: What is a Planet? . 2006-08-20 . 193–216 . Gibor . Basri . Brown . Michael E. . Michael E. Brown . 34 . 2006 . 10.1146/annurev.earth.34.031405.125058 . . astro-ph/0608417 . 2006AREPS..34..193B. 119338327 .
33. Chen . Jingjing . Kipping . David . 2016 . Probabilistic Forecasting of the Masses and Radii of Other Worlds . The Astrophysical Journal . 834 . 1 . 17 . 1603.08614 . 10.3847/1538-4357/834/1/17 . 119114880 . free . 2017ApJ...834...17C .
34. Web site: The Jovian Planets: Uranus, and Neptune . 2013-03-15 . https://web.archive.org/web/20120118184803/http://astronomy.nmsu.edu/tharriso/ast105/UranusandNeptune.html . 2012-01-18 . dead .
35. Web site: Cool Cosmos – Planets and Moons . 2019-02-11 . 2019-02-21 . https://web.archive.org/web/20190221171452/http://coolcosmos.ipac.caltech.edu/cosmic_classroom/cosmic_reference/planets.html . dead .
36. Web site: Working Group on Extrasolar Planets: Definition of a "Planet" . IAU position statement . 2003-02-28 . 2014-04-28 . https://web.archive.org/web/20141216075559/http://home.dtm.ciw.edu/users/boss/definition.html . 2014-12-16 . dead .
37. Burgasser . Adam J. . June 2008 . Brown dwarfs: Failed stars, super Jupiters . dead . . Cambridge, MA . Massachusetts Institute of Technology . 61 . 6 . 70–71 . 2008PhT....61f..70B . 10.1063/1.2947658 . https://web.archive.org/web/20130508182012/http://astro.berkeley.edu/~gmarcy/astro160/papers/brown_dwarfs_failed_stars.pdf . May 8, 2013 . March 31, 2022 . American Institute of Physics.
38. Bodenheimer . Peter . D'Angelo . Gennaro . Lissauer . Jack J. . Jack J. Lissauer . Fortney . Jonathan J. . Saumon . Didier . Deuterium Burning in Massive Giant Planets and Low-mass Brown Dwarfs Formed by Core-nucleated Accretion . The Astrophysical Journal . 2013 . 770 . 2 . 120 (13 pp.) . 10.1088/0004-637X/770/2/120 . 1305.0980 . 2013ApJ...770..120B. 118553341 .
39. Spiegel . David S. . Burrows . Adam . Milson . John A. . The Deuterium-Burning Mass Limit for Brown Dwarfs and Giant Planets . The Astrophysical Journal . 727 . 1 . 57 . 2011 . 10.1088/0004-637X/727/1/57 . 1008.5150 . 2011ApJ...727...57S. 118513110 .
40. Schneider . Jean . Dedieu . Cyril . Le Sidaner . Pierre . Savalle . Renaud . Zolotukhin . Ivan . Defining and cataloging exoplanets: The exoplanet.eu database . 2011 . 532 . 79 . . 1106.0586 . 10.1051/0004-6361/201116713 . A79 . 2011A&A...532A..79S . 55994657 .
41. Book: Schneider, Jean . 1604.00917 . Exoplanets versus brown dwarfs: the CoRoT view and the future . The CoRoT Legacy Book . July 2016 . 157 . 10.1051/978-2-7598-1876-1.c038 . 978-2-7598-1876-1. 118434022 .
42. 1506.05097 . Hatzes . Artie P. . Artie P. Hatzes . Rauer . Heike . Heike Rauer . A Definition for Giant Planets Based on the Mass-Density Relationship . 2015 . 10.1088/2041-8205/810/2/L25 . 810 . 2 . The Astrophysical Journal . L25 . 2015ApJ...810L..25H . 119111221 .
43. 1012.5676 . The Exoplanet Orbit Database . 2010 . 2011PASP..123..412W . 10.1086/659427 . 123 . 902 . . 412–422 . Wright . Jason T. . Fakhouri . Onsi . Marcy . Geoffrey W. . Geoffrey Marcy . Han . Eunkyu . Feng . Y. Katherina . Johnson . John Asher . John Johnson (astronomer) . Howard . Andrew W. . Fischer . Debra A. . Debra Fischer . Valenti . Jeff A. . Anderson . Jay . Piskunov . Nikolai . 51769219 .
44. http://exoplanetarchive.ipac.caltech.edu/docs/exoplanet_criteria.html Exoplanet Criteria for Inclusion in the Archive
45. http://www.dtm.ciw.edu/boss/definition.html Working Group on Extrasolar Planets – Definition of a "Planet"
46. Delorme . Philippe . Jonathan . Gagné . Lison . Malo . Céline . Reylé . Étienne . Artigau . Loïc . Albert . Thierry . Forveille . Xavier . Delfosse . France . Allard . Derek . Homeier . CFBDSIR2149-0403: a 4–7 Jupiter-mass free-floating planet in the young moving group AB Doradus? . Astronomy & Astrophysics . December 2012 . 1210.0305 . 10.1051/0004-6361/201219984 . 2012A&A...548A..26D . 548 . A26. 50935950 .
47. Discovery of a ~250 K Brown Dwarf at 2 pc from the Sun . . Kevin L. . Luhman . Kevin Luhman . 786 . 2 . L18 . 21 April 2014 . 10.1088/2041-8205/786/2/L18 . 1404.6501 . 2014ApJ...786L..18L. 119102654 .
48. Saumon . Didier . Marley . Mark S. . December 2008 . The Evolution of L and T Dwarfs in Color-Magnitude Diagrams . Astrophysical Journal . en . 689 . 2 . 1327–1344 . 10.1086/592734 . 0808.2611 . 2008ApJ...689.1327S . 15981010 . 0004-637X .
49. Filippazzo . Joseph C. . Rice . Emily L. . Faherty . Jacqueline K.. Jackie Faherty . Cruz . Kelle L. . Van Gordon . Mollie M. . Looper . Dagny L. . September 2015 . Fundamental Parameters and Spectral Energy Distributions of Young and Field Age Objects with Masses Spanning the Stellar to Planetary Regime . Astrophysical Journal . en . 810 . 2 . 158 . 10.1088/0004-637X/810/2/158 . 1508.01767 . 2015ApJ...810..158F . 89611607 . 0004-637X .
50. Mohanty . Subhanjoy . Jayawardhana . Ray . Huélamo . Nuria . Mamajek . Eric . March 2007 . The Planetary Mass Companion 2MASS 1207-3932B: Temperature, Mass, and Evidence for an Edge-on Disk . Astrophysical Journal . en . 657 . 2 . 1064–1091 . 10.1086/510877 . astro-ph/0610550 . 2007ApJ...657.1064M . 17326111 . 0004-637X .
51. Zhang . Zhoujian . Liu . Michael C. . Hermes . James J. . Magnier . Eugene A. . Marley . Mark S. . Tremblay . Pier-Emmanuel . Tucker . Michael A. . Do . Aaron . Payne . Anna V. . Shappee . Benjamin J. . February 2020 . COol Companions ON Ultrawide orbiTS (COCONUTS). I. A High-Gravity T4 Benchmark around an Old White Dwarf and A Re-Examination of the Surface-Gravity Dependence of the L/T Transition . The Astrophysical Journal . en . 891 . 2 . 171 . 10.3847/1538-4357/ab765c . 2002.05723 . 2020ApJ...891..171Z . 211126544 . free .
52. Smart . Richard L. . Bucciarelli . Beatrice . Jones . Hugh R. A. . Marocco . Federico . Andrei . Alexandre Humberto . Goldman . Bertrand . Méndez . René A. . d'Avila . Victor de A. . Burningham . Ben . Camargo . Julio Ignácio Bueno de . Crosta . Maria Teresa . Mario . Daprà . James S. . Jenkins . Regis . Lachaume . Mario G. . Lattanzi . Jucira L. . Penna . David J. . Pinfield . Dario Nepomuceno . da Silva Neto . Alessandro . Sozzetti . Alberto . Vecchiato . December 2018 . Parallaxes of Southern Extremely Cool objects III: 118 L and T dwarfs . MNRAS . en . 481 . 3 . 3548–3562 . 10.1093/mnras/sty2520 . free . 1811.00672 . 2018MNRAS.481.3548S . 119390019 . 0035-8711 .
53. Burrows . Adam . Hubbard . William B. . Lunine . Jonathan I. . Liebert . James . 2001 . The theory of brown dwarfs and extrasolar giant planets . . 73 . 3 . 719–765 . 10.1103/RevModPhys.73.719 . 2001RvMP...73..719B . astro-ph/0103383 . 204927572 .
54. http://spider.ipac.caltech.edu/staff/davy/2mass/science/comparison.html "An Artist's View of Brown Dwarf Types"
55. 10.1088/0004-637X/695/2/1517 . 2009ApJ...695.1517L . The Physical Properties of Four ~600 K T Dwarfs . The Astrophysical Journal . 695 . 2 . 1517–1526 . Leggett . Sandy K. . Cushing . Michael C. . Saumon . Didier . Marley . Mark S. . Roellig . Thomas L. . Warren . Stephen J. . Burningham . Ben . Jones . Hugh R. A. . Kirkpatrick . J. Davy . Lodieu . Nicolas . Lucas . Philip W. . Mainzer . Amy K. . Martín . Eduardo L. . McCaughrean . Mark J. . Pinfield . David J. . Sloan . Gregory C. . Smart . Richard L. . Tamura . Motohide . Van Cleve . Jeffrey . 2009 . 0901.4093 . 44050900 . .
56. 10.1051/0004-6361:20079317 . 2008A&A...482..961D . CFBDS J005910.90-011401.3: Reaching the T–Y brown dwarf transition? . Astronomy and Astrophysics . 482 . 3 . 961–971 . 2008 . Delorme . Philippe . Delfosse . Xavier . Albert . Loïc . Artigau . Étienne . Forveille . Thierry . Reylé . Céline . Allard . France . Homeier . Derek . Robin . Annie C. . Willott . Chris J. . Liu . Michael C. . Dupuy . Trent J. . 0802.4387 . 847552 .
57. Beiler . Samuel A. . Cushing . Michael C. . Kirkpatrick . J. Davy . Schneider . Adam C. . Mukherjee . Sagnick . Marley . Mark S. . 2023-07-01 . The First JWST Spectral Energy Distribution of a Y Dwarf . The Astrophysical Journal . 951 . 2 . L48 . 10.3847/2041-8213/ace32c . 0004-637X. 2306.11807 . 2023ApJ...951L..48B . free .
58. Leggett . S. K. . Tremblin . Pascal . 25 Sep 2023 . The First Y Dwarf Data From JWST Show That Dynamic and Diabatic Processes Regulate Cold Brown Dwarf Atmospheres . The Astrophysical Journal. 959 . 2 . 86 . 10.3847/1538-4357/acfdad . 2309.14567 . 2023ApJ...959...86L . free .
59. Peter R. M. . Eisenhardt . Ultracool Field Brown Dwarf Candidates Selected at 4.5 microns . The Astronomical Journal . 139 . 6 . 2455 . 1004.1436 . 2010 . Griffith . Roger L. . Stern . Daniel . Wright . Edward L. . Edward L. Wright . Ashby . Matthew L. N. . Brodwin . Mark . Brown . Michael J. I. . Bussmann . R. S. . Dey . Arjun . Ghez . Andrea Mia . Andrea M. Ghez . Glikman . Eilat . Gonzalez . Anthony H. . Kirkpatrick . J. Davy . Konopacky . Quinn . Mainzer . Amy . Vollbach . David . Wright . Shelley A. . 10.1088/0004-6256/139/6/2455 . 2010AJ....139.2455E. 2019463 .
60. Luhman . Kevin L. . Burgasser . Adam J. . Bochanski . John J. . Discovery of a candidate for the coolest known brown dwarf . The Astrophysical Journal Letters . 20 March 2011 . 730 . 1 . L9 . 10.1088/2041-8205/730/1/L9 . 2011ApJ...730L...9L . 1102.5411. 54666396 .
61. Rodriguez . David R. . Zuckerman . Benjamin . Benjamin Zuckerman . Melis . Carl . Song . Inseok . The ultra cool brown dwarf companion of WD 0806-661B: age, mass, and formation mechanism . The Astrophysical Journal . 10 May 2011 . 732 . 2 . L29 . 10.1088/2041-8205/732/2/L29 . 2011ApJ...732L..29R . 1103.3544. 118382542 .
62. Liu . Michael C. . Philippe . Delorme . Trent J. . Dupuy . Brendan P. . Bowler . Loïc . Albert . Étienne . Artigau . Céline . Reylé . Thierry . Forveille . Xavier . Delfosse . 28 Feb 2011 . CFBDSIR J1458+1013B: A Very Cold (>T10) Brown Dwarf in a Binary System . The Astrophysical Journal . 740 . 2 . 108 . 1103.0014 . 10.1088/0004-637X/740/2/108 . 2011ApJ...740..108L. 118344589 .
63. Plait . Phil . WISE finds coolest brown dwarfs ever seen! . Discover Magazine . 24 August 2011 . 30 October 2013 . 26 July 2014 . https://web.archive.org/web/20140726133222/http://blogs.discovermagazine.com/badastronomy/2011/08/24/wise-finds-coolest-brown-dwarfs-ever-seen/#.UnGKkHDkudE . dead .
64. Web site: Whitney . Clavin . WISE Finds Few Brown Dwarfs Close To Home . 8 June 2012 . NASA . 30 October 2013 . 15 March 2014 . https://web.archive.org/web/20140315070839/http://www.nasa.gov/mission_pages/WISE/news/wise20120608.html . dead .
65. Kirkpatrick . J. Davy . Cushing . Michael C. . Gelino . Christopher R. . Griffith . Roger L. . Skrutskie . Michael F. . Marsh . Kenneth A. . Wright . Edward L. . Mainzer . A. . Eisenhardt . Peter R. . McLean . Ian S. . Thompson . Maggie A. . Bauer . James M. . Benford . Dominic J. . Bridge . Carrie R. . Lake . Sean E. . 2011-12-01 . The First Hundred Brown Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE) . The Astrophysical Journal Supplement Series . 197 . 2 . 19 . 1108.4677 . 2011ApJS..197...19K . 10.1088/0067-0049/197/2/19 . 0067-0049 . 16850733.
66. Cushing . Michael C. . Kirkpatrick . J. Davy . Gelino . Christopher R. . Griffith . Roger L. . Skrutskie . Michael F. . Mainzer . A. . Marsh . Kenneth A. . Beichman . Charles A. . Burgasser . Adam J. . Prato . Lisa A. . Simcoe . Robert A. . Marley . Mark S. . Saumon . D. . Freedman . Richard S. . Eisenhardt . Peter R. . 2011-12-01 . The Discovery of Y Dwarfs using Data from the Wide-field Infrared Survey Explorer (WISE) . The Astrophysical Journal . 743 . 1 . 50 . 1108.4678 . 2011ApJ...743...50C . 10.1088/0004-637X/743/1/50 . 0004-637X . 286881.
67. Kirkpatrick . J. Davy . Gelino . Christopher R. . Cushing . Michael C. . Mace . Gregory N. . Griffith . Roger L. . Skrutskie . Michael F. . Marsh . Kenneth A. . Wright . Edward L. . Eisenhardt . Peter R. . McLean . Ian S. . Mainzer . Amanda K. . Burgasser . Adam J. . Tinney . C. G. . Parker . Stephen . Salter . Graeme . 2012-07-01 . Further Defining Spectral Type "Y" and Exploring the Low-mass End of the Field Brown Dwarf Mass Function . The Astrophysical Journal . 753 . 2 . 156 . 1205.2122 . 2012ApJ...753..156K . 10.1088/0004-637X/753/2/156 . 0004-637X.
68. News: Morse . Jon . Discovered: Stars as Cool as the Human Body . 24 August 2011 . https://web.archive.org/web/20111007124027/http://science.nasa.gov/science-news/science-at-nasa/2011/23aug_coldeststars/ . 7 October 2011 . dead .
69. Beichman . Charles A. . Gelino . Christopher R. . Kirkpatrick . J. Davy . Barman . Travis S. . Marsh . Kenneth A. . Cushing . Michael C. . Wright . Edward L. . The Coldest Brown Dwarf (or Free-floating Planet)?: The Y Dwarf WISE 1828+2650 . 2013 . . 764 . 1 . 101 . 1301.1669 . 10.1088/0004-637X/764/1/101 . 2013ApJ...764..101B. 118575478 .
70. Tinney . C. G. . Faherty . Jacqueline K. . Kirkpatrick . J. Davy . Wright . Edward L. . Gelino . Christopher R. . Cushing . Michael C. . Griffith . Roger L. . Salter . Graeme . 2012-11-01 . WISE J163940.83-684738.6: A Y Dwarf Identified by Methane Imaging . The Astrophysical Journal . 759 . 1 . 60 . 1209.6123 . 2012ApJ...759...60T . 10.1088/0004-637X/759/1/60 . 0004-637X.
71. Web site: NASA's Spitzer and WISE Telescopes Find Close, Cold Neighbor of Sun . NASA.gov . Whitney . Clavin . J. D. . Harrington . 25 April 2014 . https://web.archive.org/web/20140426004939/http://www.nasa.gov/jpl/wise/spitzer-coldest-brown-dwarf-20140425 . 26 April 2014 . live .
72. Cushing . Michael C. . Kirkpatrick . J. Davy . Gelino . Christopher R. . Mace . Gregory N. . Skrutskie . Michael F. . Gould . Andrew . 2014-05-01 . Three New Cool Brown Dwarfs Discovered with the Wide-field Infrared Survey Explorer (WISE) and an Improved Spectrum of the Y0 Dwarf WISE J041022.71+150248.4 . The Astronomical Journal . 147 . 5 . 113 . 1402.1378 . 2014AJ....147..113C . 10.1088/0004-6256/147/5/113 . 0004-6256.
73. Tinney . C. G. . Faherty . Jacqueline K. . Kirkpatrick . J. Davy . Cushing . Mike . Morley . Caroline V. . Wright . Edward L. . 2014-11-01 . The Luminosities of the Coldest Brown Dwarfs . The Astrophysical Journal . 796 . 1 . 39 . 1410.0746 . 2014ApJ...796...39T . 10.1088/0004-637X/796/1/39 . 0004-637X.
74. Tinney . C. G. . Kirkpatrick . J. Davy . Faherty . Jacqueline K. . Mace . Gregory N. . Cushing . Mike . Gelino . Christopher R. . Burgasser . Adam J. . Sheppard . Scott S. . Wright . Edward L. . 2018-06-01 . New Y and T Dwarfs from WISE Identified by Methane Imaging . The Astrophysical Journal Supplement Series . 236 . 2 . 28 . 1804.00362 . 2018ApJS..236...28T . 10.3847/1538-4365/aabad3 . 0067-0049 . free.
75. Dupuy . Trent J. . Liu . Michael C. . Leggett . S. K. . 2015-04-01 . Discovery of a Low-luminosity, Tight Substellar Binary at the T/Y Transition . The Astrophysical Journal . 803 . 2 . 102 . 1502.04707 . 2015ApJ...803..102D . 10.1088/0004-637X/803/2/102 . 0004-637X . 118507808 . 2152/35100.
76. Schneider . Adam C. . Cushing . Michael C. . Kirkpatrick . J. Davy . Gelino . Christopher R. . Mace . Gregory N. . Wright . Edward L. . Eisenhardt . Peter R. . Skrutskie . M. F. . Griffith . Roger L. . Marsh . Kenneth A. . 2015-05-01 . Hubble Space Telescope Spectroscopy of Brown Dwarfs Discovered with the Wide-field Infrared Survey Explorer . The Astrophysical Journal . 804 . 2 . 92 . 1502.05365 . 2015ApJ...804...92S . 10.1088/0004-637X/804/2/92 . 0004-637X.
77. Marocco . Federico . Caselden . Dan . Meisner . Aaron M. . Kirkpatrick . J. Davy . Wright . Edward L. . Faherty . Jacqueline K. . Gelino . Christopher R. . Eisenhardt . Peter R. M. . Fowler . John W. . Cushing . Michael C. . Cutri . Roc M. . Garcia . Nelson . Jarrett . Thomas H. . Koontz . Renata . Mainzer . Amanda . 2019 . CWISEP J193518.59 − 154620.3: An Extremely Cold Brown Dwarf in the Solar Neighborhood Discovered with CatWISE . The Astrophysical Journal . 881 . 1 . 17 . 1906.08913 . 2019ApJ...881...17M . 10.3847/1538-4357/ab2bf0 . 195316522 . free . Elijah J. . Marchese . Bahram . Mobasher . David J. . Schlegel . Daniel . Stern . Harry I. . Teplitz.
78. Web site: 2024-01-09 . NASA's Webb Finds Signs of Possible Aurorae on Isolated Brown Dwarf – NASA . 2024-01-10 . en-US.
79. Bardalez Gagliuffi . Daniella C. . Faherty . Jacqueline K. . Backyard Worlds: Planet 9 Citizen Science Collaboration . Schneider . Adam C. . Meisner . Aaron M. . Caselden . Dan . Colin . Guillaume . Goodman . Sam . Kirkpatrick . J. Davy . Kuchner . Marc J. . Gagne . Jonathan . Logsdon . Sarah E. . Burgasser . Adam J. . Allers . Katelyn N. . Debes . John H. . January 2020 . WISE J0830+2837: the first Y dwarf from Backyard Worlds: Planet 9 . AAS . en . 52 . 132.06 . 2020AAS...23513206B . Wisniewski . John.
80. Eisenhardt . Peter R. M. . Marocco . Federico . Fowler . John W. . Meisner . Aaron M. . Kirkpatrick . J. Davy . Garcia . Nelson . Jarrett . Thomas H. . Koontz . Renata . Marchese . Elijah J. . Stanford . S. Adam . Caselden . Dan . The CatWISE Preliminary Catalog: Motions from WISE and NEOWISE Data . The Astrophysical Journal Supplement Series . 2020 . en . 247 . 2 . 69 . 10.3847/1538-4365/ab7f2a . 1908.08902 . 2020ApJS..247...69E . 201645245 . free .
81. Meisner . Aaron M. . Caselden . Dan . Kirkpatrick . J. Davy . Marocco . Federico . Gelino . Christopher R. . Cushing . Michael C. . Eisenhardt . Peter R. M. . Wright . Edward L. . Faherty . Jacqueline K. . Koontz . Renata . Marchese . Elijah J. . Expanding the Y Dwarf Census with Spitzer Follow-up of the Coldest CatWISE Solar Neighborhood Discoveries . The Astrophysical Journal . 889 . 2 . 74 . 1911.12372 . 10.3847/1538-4357/ab6215 . 2020 . 2020ApJ...889...74M . 208513044 . free .
82. Marocco . Federico . Kirkpatrick . J. Davy . Meisner . Aaron M. . Caselden . Dan . Eisenhardt . Peter R. M. . Cushing . Michael C. . Faherty . Jacqueline K. . Gelino . Christopher R. . Wright . Edward L. . Improved infrared photometry and a preliminary parallax measurement for the extremely cold brown dwarf CWISEP J144606.62-231717.8 . The Astrophysical Journal . 1912.07692 . en . 888 . 2 . L19 . 2020ApJ...888L..19M . 10.3847/2041-8213/ab6201 . 2020 . 209386563 . free .
83. Kirkpatrick . J. Davy . Gelino . Christopher R. . Faherty . Jacqueline K. . Meisner . Aaron M. . Caselden . Dan . Schneider . Adam C. . Marocco . Federico . Cayago . Alfred J. . Smart . R. L. . Eisenhardt . Peter R. . Kuchner . Marc J. . Wright . Edward L. . Cushing . Michael C. . Allers . Katelyn N. . Bardalez Gagliuffi . Daniella C. . 2021-03-01 . The Field Substellar Mass Function Based on the Full-sky 20 pc Census of 525 L, T, and Y Dwarfs . The Astrophysical Journal Supplement Series . 253 . 1 . 7 . 2011.11616 . 2021ApJS..253....7K . 10.3847/1538-4365/abd107 . 0067-0049 . free.
84. Schneider . Adam C. . Meisner . Aaron M. . Gagné . Jonathan . Faherty . Jacqueline K. . Marocco . Federico . Burgasser . Adam J. . Kirkpatrick . J. Davy . Kuchner . Marc J. . Gramaize . Léopold . Rothermich . Austin . Brooks . Hunter . Vrba . Frederick J. . Bardalez Gagliuffi . Daniella . Caselden . Dan . Cushing . Michael C. . 2021-11-01 . Ross 19B: An Extremely Cold Companion Discovered via the Backyard Worlds: Planet 9 Citizen Science Project . The Astrophysical Journal . 921 . 2 . 140 . 2108.05321 . 2021ApJ...921..140S . 10.3847/1538-4357/ac1c75 . 0004-637X . free.
85. Kirkpatrick . J. Davy . Marocco . Federico . Gelino . Christopher R. . Raghu . Yadukrishna . Faherty . Jacqueline K. . Bardalez Gagliuffi . Daniella C. . Schurr . Steven D. . Apps . Kevin . Schneider . Adam C. . Meisner . Aaron M. . Kuchner . Marc J. . Caselden . Dan . Smart . R. L. . Casewell . S. L. . Raddi . Roberto . 1 . December 2023 . The Initial Mass Function Based on the Full-sky 20-pc Census of ∼3,600 Stars and Brown Dwarfs . The Astrophysical Journal Supplement Series . en . 2312.03639 . 2024ApJS..271...55K . Kesseli . Aurora . Stevnbak Andersen . Nikolaj . Antonini . Edoardo . Beaulieu . Paul . Bickle . Thomas P. . Bilsing . Martin . Chieng . Raymond . Colin . Guillaume . Deen . Sam . Dereveanco . Alexandru . Doll . Katharina . Durantini Luca . Hugo A. . Frazer . Anya . Gantier . Jean Marc . Gramaize . Léopold . Grant . Kristin . Hamlet . Leslie K. . Higashimura . Hiro . Hyogo . Michiharu . Jałowiczor . Peter A. . Jonkeren . Alexander . Kabatnik . Martin . Kiwy . Frank . Martin . David W. . Michaels . Marianne N. . Pendrill . William . Pessanha Machado . Celso . Pumphrey . Benjamin . Rothermich . Austin . Russwurm . Rebekah . Sainio . Arttu . Sanchez . John . Sapelkin-Tambling . Fyodor Theo . Schümann . Jörg . Selg-Mann . Karl . Singh . Harshdeep . Stenner . Andres . Sun . Guoyou . Tanner . Christopher . Thévenot . Melina . Ventura . Maurizio . Voloshin . Nikita V. . Walla . Jim . Wedracki . Zbigniew . Adorno . Jose I. . Aganze . Christian . Allers . Katelyn N. . Brooks . Hunter . Burgasser . Adam J. . Calamari . Emily . Connor . Thomas . Costa . Edgardo . Eisenhardt . Peter R. . Gagné . Jonathan . Gerasimov . Roman . Gonzales . Eileen C. . Hsu . Chih-Chun . Kiman . Rocio . Li . Guodong . Low . Ryan . Mamajek . Eric . Pantoja . Blake M. . Popinchalk . Mark . Rees . Jon M. . Stern . Daniel . Suárez . Genaro . Theissen . Christopher . Tsai . Chao-Wei . Vos . Johanna M. . Zurek . David . The Backyard Worlds: Planet 9 Collaboration. 271 . 2 . 55 . 10.3847/1538-4365/ad24e2 . free .
86. Robbins . Grady . Meisner . Aaron M. . Schneider . Adam C. . Burgasser . Adam J. . Kirkpatrick . J. Davy . Gagné . Jonathan . Hsu . Chih-Chun . Moranta . Leslie . Casewell . Sarah . Marocco . Federico . Gerasimov . Roman . Faherty . Jacqueline K. . Kuchner . Marc J. . Caselden . Dan . Cushing . Michael C. . 2023-11-01 . CWISE J105512.11+544328.3: A Nearby Y Dwarf Spectroscopically Confirmed with Keck/NIRES . The Astrophysical Journal . 958 . 1 . 94 . 2310.09524 . 2023ApJ...958...94R . 10.3847/1538-4357/ad0043 . 0004-637X . free.
87. Mullally . Susan E. . Debes . John . Cracraft . Misty . Mullally . Fergal . Poulsen . Sabrina . Albert . Loic . Thibault . Katherine . Reach . William T. . Hermes . J. J. . Barclay . Thomas . Kilic . Mukremin . Quintana . Elisa V. . 24 Jan 2024 . JWST Directly Images Giant Planet Candidates Around Two Metal-Polluted White Dwarf Stars . The Astrophysical Journal Letters . 962 . 2 . L32 . 10.3847/2041-8213/ad2348 . free . 2401.13153. 2024ApJ...962L..32M .
88. Bardalez Gagliuffi . Daniella C. . Faherty . Jacqueline K. . Schneider . Adam C. . Meisner . Aaron . Caselden . Dan . Colin . Guillaume . Goodman . Sam . Kirkpatrick . J. Davy . Kuchner . Marc . Gagné . Jonathan . Logsdon . Sarah E. . Burgasser . Adam J. . Allers . Katelyn . Debes . John . Wisniewski . John . 2020-06-01 . WISEA J083011.95+283716.0: A Missing Link Planetary-mass Object . The Astrophysical Journal . 895 . 2 . 145 . 10.3847/1538-4357/ab8d25 . 2004.12829 . 2020ApJ...895..145B . 216553879 . 0004-637X . free .
89. Web site: Spectral type codes. simbad.u-strasbg.fr. 2020-03-06.
90. Burningham . Ben . Smith . Leigh . Cardoso . Cátia V. . Lucas . Philip W. . Burgasser . Adam J. . Jones . Hugh R. A. . Smart . Richard L. . May 2014 . The discovery of a T6.5 subdwarf . . en . 440 . 1 . 359–364 . 10.1093/mnras/stu184 . free . 1401.5982 . 2014MNRAS.440..359B . 119283917 . 0035-8711 .
91. Cruz . Kelle L. . Kirkpatrick . J. Davy . Burgasser . Adam J. . February 2009 . Young L Dwarfs Identified in the Field: A Preliminary Low-Gravity, Optical Spectral Sequence from L0 to L5 . The Astronomical Journal . en . 137 . 2 . 3345–3357 . 10.1088/0004-6256/137/2/3345 . 0812.0364 . 2009AJ....137.3345C . 15376964 . 0004-6256 .
92. Looper . Dagny L. . Kirkpatrick . J. Davy . Cutri . Roc M. . Barman . Travis . Burgasser . Adam J. . Cushing . Michael C. . Roellig . Thomas . McGovern . Mark R. . McLean . Ian S. . Rice . Emily . Swift . Brandon J. . October 2008 . Discovery of Two Nearby Peculiar L Dwarfs from the 2MASS Proper-Motion Survey: Young or Metal-Rich? . Astrophysical Journal . en . 686 . 1 . 528–541 . 10.1086/591025 . 0806.1059 . 2008ApJ...686..528L . 18381182 . 0004-637X .
93. Kirkpatrick . J. Davy. Looper . Dagny L. . Burgasser . Adam J. . Schurr . Steven D. . Cutri . Roc M. . Cushing . Michael C. . Cruz . Kelle L. . Sweet . Anne C. . Knapp . Gillian R. . Barman . Travis S. . Bochanski . John J. . September 2010 . Discoveries from a Near-infrared Proper Motion Survey Using Multi-epoch Two Micron All-Sky Survey Data . Astrophysical Journal Supplement Series . en . 190 . 1 . 100–146 . 10.1088/0067-0049/190/1/100 . 1008.3591 . 2010ApJS..190..100K . 118435904 . 0067-0049 .
94. Faherty . Jacqueline K. . Riedel . Adric R. . Cruz . Kelle L. . Gagne . Jonathan . Filippazzo . Joseph C. . Lambrides . Erini . Fica . Haley . Weinberger . Alycia . Thorstensen . John R. . Tinney . Chris G. . Baldassare . Vivienne . July 2016 . Population Properties of Brown Dwarf Analogs to Exoplanets . Astrophysical Journal Supplement Series . en . 225 . 1 . 10 . 10.3847/0067-0049/225/1/10 . 1605.07927 . 2016ApJS..225...10F . 118446190 . 0067-0049 . free .
95. Web site: Colour-magnitude data . Neill . Reid . 15/07/02 (unless a typo, dates to ca. 2004, otherwise 2002 --> . www.stsci.edu . 2020-03-06 .
96. 10.3847/1538-3881/ac66d2. Precise Dynamical Masses of ε Indi Ba and Bb: Evidence of Slowed Cooling at the L/T Transition . 2022 . Chen . Minghan . Li . Yiting . Brandt . Timothy D. . Dupuy . Trent J. . Cardoso . Cátia V. . McCaughrean . Mark J. . The Astronomical Journal . 163 . 6 . 288 . 2205.08077 . 2022AJ....163..288C . 248834536 . free .
97. Web site: NASA Space Telescopes See Weather Patterns in Brown Dwarf . Hubblesite . NASA . 8 January 2013 . 2 April 2014 . https://web.archive.org/web/20140402162957/http://hubblesite.org/newscenter/archive/releases/star/brown-dwarf/2013/02/ . dead .
98. Web site: Astronomers Clock High Winds on Object Outside Our Solar System. CNN.com. 9 April 2020 . CNN. 11 April 2020.
99. Route . Matthew . Wolszczan . Alexander . The Second Arecibo Search for 5 GHz Radio Flares from Ultracool Dwarfs . The Astrophysical Journal . 20 October 2016 . 830 . 2 . 85 . 10.3847/0004-637X/830/2/85 . 1608.02480 . 2016ApJ...830...85R . 119279978 . free .
100. Rutledge . Robert E. . Basri . Gibor . Martín . Eduardo L. . Bildsten . Lars . Chandra Detection of an X-Ray Flare from the Brown Dwarf LP 944-20 . The Astrophysical Journal . 1 August 2000 . 538 . 2 . L141–L144 . astro-ph/0005559 . 2000ApJ...538L.141R . 10.1086/312817 . 17800872 .
101. Berger . Edo . Ball . Steven . Becker . Kate M. . Clarke . Melanie . Frail . Dale A. . Fukuda . Therese A. . Hoffman . Ian M. . Mellon . Richard . Momjian . Emmanuel . Murphy . Nathanial W. . Teng . Stacey H. . Woodruff . Timothy . Zauderer . B. Ashley . Zavala . Robert T. . Discovery of radio emission from the brown dwarf LP944-20 . Nature . 2001-03-15 . 410 . 6826 . 338–340 . astro-ph/0102301 . 2001Natur.410..338B . 10.1038/35066514 . 11268202 . 4411256 . https://web.archive.org/web/20210427121818/https://cds.cern.ch/record/487607 . dead . 2021-04-27 . Submitted manuscript .
102. Gael . Chauvin . Ben . Zuckerman . Anne-Marie . Lagrange . Yes, it is the Image of an Exoplanet: Astronomers Confirm the First Image of a Planet Outside of Our Solar System . European Southern Observatory . en . 2020-02-09 .
103. Luhman . Kevin L. . April 2013 . Discovery of a Binary Brown Dwarf at 2 pc from the Sun . Astrophysical Journal Letters . en . 767 . 1 . L1 . 10.1088/2041-8205/767/1/L1 . 1303.2401 . 2013ApJ...767L...1L . 8419422 . 0004-637X .
104. Web site: April 14, 2003 . X-rays from a Brown Dwarf's Corona . March 19, 2010 . https://web.archive.org/web/20101230000830/http://www.williams.edu/Astronomy/jay/chapter18_etu6.html . December 30, 2010 . dead .
105. Route . Matthew . Radio-flaring Ultracool Dwarf Population Synthesis . The Astrophysical Journal . 10 August 2017 . 845 . 1 . 66 . 10.3847/1538-4357/aa7ede . 1707.02212 . 2017ApJ...845...66R . 118895524 . free .
106. Kao . Melodie M. . Gregg . Hallinan . J. Sebastian . Pineda . David . Stevenson . Adam J. . Burgasser . The Strongest Magnetic Fields on the Coolest Brown Dwarfs . The Astrophysical Journal Supplement Series . 31 July 2018 . 237 . 2 . 25 . 10.3847/1538-4365/aac2d5 . 1808.02485 . 2018ApJS..237...25K . 118898602 . free .
107. Route . Matthew . Is WISEP J060738.65+242953.4 Really A Magnetically Active, Pole-on L Dwarf? . The Astrophysical Journal . 10 July 2017 . 843 . 2 . 115 . 10.3847/1538-4357/aa78ab . 1706.03010 . 2017ApJ...843..115R . 119056418 . free .
108. Route . Matthew . The Discovery of Solar-like Activity Cycles Beyond the End of the Main Sequence? . The Astrophysical Journal Letters . 20 October 2016 . 830 . 2 . L27 . 10.3847/2041-8205/830/2/L27 . 1609.07761 . 2016ApJ...830L..27R . 119111063 . free .
109. Web site: O'Neill . Ian . 12 June 2012 . Brown Dwarfs, Runts of Stellar Litter, Rarer than Thought . 2012-12-28 . Space.com.
110. Muzic . Koraljka . Schoedel . Rainer . Scholz . Alexander . Geers . Vincent C. . Jayawardhana . Ray . Ascenso . Joana . Cieza . Lucas A. . 2017-07-02 . The low-mass content of the massive young star cluster RCW 38 . Monthly Notices of the Royal Astronomical Society . 471 . 3 . 3699–3712 . 1707.00277 . 2017MNRAS.471.3699M . 10.1093/mnras/stx1906 . free . 0035-8711 . 54736762.
111. Apai . Dániel . Karalidi . T. . Marley . Mark S. . Yang . H. . Flateau . D. . Metchev . S. . Cowan . N. B. . Buenzli . E. . Burgasser . Adam J. . Radigan . J. . Artigau . Étienne . Lowrance . P. . 2017 . Zones, spots, and planetary-scale waves beating in brown dwarf atmospheres . Science . 357 . 6352 . 683–687 . 2017Sci...357..683A . 10.1126/science.aam9848 . 28818943 . free.
112. Web site: Gohd . Chelsea . 19 August 2020 . Volunteers spot almost 100 cold brown dwarfs near our sun . Space.com.
113. https://www.space.com/brown-dwarf-alien-weather-report-jwst Alien weather report: James Webb Space Telescope detects hot, sandy wind on 2 brown dwarfs; Space.com
114. Web site: [e-mail] . Are the Coolest Brown Dwarfs Loners? . 2023-04-16 . www.noirlab.edu . en.
115. Fontanive . Clémence . Biller . Beth . Bonavita . Mariangela . Allers . Katelyn . 2018-09-01 . Constraining the multiplicity statistics of the coolest brown dwarfs: binary fraction continues to decrease with spectral type . Monthly Notices of the Royal Astronomical Society . 479 . 2 . 2702–2727 . 10.1093/mnras/sty1682 . free . 1806.08737 . 2018MNRAS.479.2702F . 0035-8711.
116. Opitz . Daniela . Tinney . C. G. . Faherty . Jacqueline . Sweet . Sarah . Gelino . Christopher R. . Kirkpatrick . J. Davy . 2016-02-24 . Searching for Binary Y dwarfs with the Gemini Multi-Conjugate Adaptive Optics System (GeMS) . The Astrophysical Journal . 819 . 1 . 17 . 10.3847/0004-637X/819/1/17 . 1601.05508 . 2016ApJ...819...17O . 3208550 . 1538-4357 . free .
117. Calissendorff . Per . De Furio . Matthew . Meyer . Michael . Albert . Loïc . Aganze . Christian . Ali-Dib . Mohamad . Gagliuffi . Daniella C. Bardalez . Baron . Frederique . Beichman . Charles A. . Burgasser . Adam J. . Cushing . Michael C. . Faherty . Jacqueline Kelly . Fontanive . Clémence . Gelino . Christopher R. . Gizis . John E. . 2023-03-29 . JWST/NIRCam Discovery of the First Y+Y Brown Dwarf Binary: WISE J033605.05–014350.4 . The Astrophysical Journal Letters . 947 . 2 . L30 . 10.3847/2041-8213/acc86d . 2303.16923 . 2023ApJ...947L..30C . 257833714 . free .
118. Hervé . Bouy . Weighing Ultra-Cool Stars – Large Ground-Based Telescopes and Hubble Team-Up to Perform First Direct Brown Dwarf Mass Measurement . European Southern Observatory . en . 2019-12-11 .
119. Bouy . Hervé . Duchêne . Gaspard . Köhler . Rainer . Brandner . Wolfgang . Bouvier . Jérôme . Martín . Eduardo L. . Ghez . Andrea Mia . Delfosse . Xavier . Forveille . Thierry . Allard . France . Baraffe . Isabelle . Gibor . Basri . Laird M. . Close . Caer E. . McCabe . 2004-08-01 . First determination of the dynamical mass of a binary L dwarf . Astronomy & Astrophysics . en . 423 . 1 . 341–352 . astro-ph/0405111 . 10.1051/0004-6361:20040551 . 0004-6361 . 2004A&A...423..341B . 3149721 .
120. Bedin . Luigi R. . Pourbaix . Dimitri . Apai . Dániel . Burgasser . Adam J. . Buenzli . Esther . Boffin . Henri M. J. . Libralato . Mattia . 2017-09-01 . Hubble Space Telescope astrometry of the closest brown dwarf binary system – I. Overview and improved orbit . Monthly Notices of the Royal Astronomical Society . en . 470 . 1 . 1140–1155 . 1706.00657 . 10.1093/mnras/stx1177 . free . 0035-8711 . 10150/625503 . 119385778 .
121. Luhman . Kevin L. . 2004-10-10 . The First Discovery of a Wide Binary Brown Dwarf . The Astrophysical Journal . en . 614 . 1 . 398–403 . astro-ph/0407344 . 10.1086/423666 . 0004-637X . 2004ApJ...614..398L . 11733526 .
122. Reipurth. Bo. Clarke. Cathie. June 2003. Brown Dwarfs as Ejected Stellar Embryos: Observational Perspectives. IAUS. en. 211. 13–22. 1743-9221. 2003IAUS..211...13R. astro-ph/0209005. 10.1017/s0074180900210188. 16822178 .
123. Faherty . Jacqueline K. . Goodman . Sam . Caselden . Dan . Colin . Guillaume . Kuchner . Marc J. . Meisner . Aaron M. . Gagné . Jonathan . Schneider . Adam C. . Gonzales . Eileen C. . Bardalez Gagliuffi . Daniella C. . Logsdon . Sarah E. . WISE2150-7520AB: A very low mass, wide co-moving brown dwarf system discovered through the citizen science project Backyard Worlds: Planet 9 . The Astrophysical Journal . 889 . 2 . 176 . 1911.04600 . 10.3847/1538-4357/ab5303 . 2020 . 2020ApJ...889..176F . 207863267 . free .
124. Grether . Daniel . Lineweaver . Charles H. . 2006-04-01 . How Dry is the Brown Dwarf Desert? Quantifying the Relative Number of Planets, Brown Dwarfs, and Stellar Companions around Nearby Sun-like Stars . The Astrophysical Journal . 640 . 2 . 1051–1062 . 10.1086/500161 . astro-ph/0412356 . 2006ApJ...640.1051G . 8563521 . 0004-637X.
125. Page . Emma . Pepper . Joshua . Kane . Stephen . Zhou . George . Addison . Brett . Wright . Duncan . Wittenmyer . Robert . Johnson . Marshall . Evans . Philip . Collins . Karen . Hellier . Coel . Jensen . Eric . Stassun . Keivan . Rodriguez . Joseph . 2022-06-01 . TOI-1994b: An Eccentric Brown Dwarf Transiting a Subgiant . American Astronomical Society Meeting Abstracts . 54 . 6 . 305.21. 2022AAS...24030521P .
126. Web site: Exoplanet Criteria for Inclusion in the Exoplanet Archive . 2023-04-16 . exoplanetarchive.ipac.caltech.edu.
127. Web site: Working Group on Extrasolar Planets . 2023-04-16 . w.astro.berkeley.edu.
128. Farihi . Jay . Christopher . Micol . October 2004 . A Possible Brown Dwarf Companion to the White Dwarf GD 1400 . The Astronomical Journal . en . 128 . 4 . 1868 . astro-ph/0407036 . 10.1086/423919 . 1538-3881 . 2004AJ....128.1868F . 119530628 .
129. Meisner . Aaron M. . Faherty . Jacqueline K. . Kirkpatrick . J. Davy . Schneider . Adam C. . Caselden . Dan . Gagné . Jonathan . Kuchner . Marc J. . Burgasser . Adam J. . Casewell . Sarah L. . Debes . John H. . Artigau . Étienne . Bardalez Gagliuffi . Daniella C. . Logsdon . Sarah E. . Kiman . Rocio . Allers . Katelyn . 2020-08-01 . Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project . The Astrophysical Journal . 899 . 2 . 123 . 10.3847/1538-4357/aba633 . 2008.06396 . 2020ApJ...899..123M . 221135837 . 0004-637X . free .
130. French . Jenni R. . Casewell . Sarah L. . Dupuy . Trent J. . Debes . John H. . Manjavacas . Elena . Martin . Emily C. . Xu . Siyi . 2023-03-01 . Discovery of a resolved white dwarf–brown dwarf binary with a small projected separation: SDSS J222551.65+001637.7AB . Monthly Notices of the Royal Astronomical Society . 519 . 4 . 5008–5016 . 10.1093/mnras/stac3807 . free . 2301.02101 . 2023MNRAS.519.5008F . 0035-8711.
131. Leggett . S. K. . Tremblin . P. . Esplin . T. L. . Luhman . K. L. . Morley . Caroline V. . 2017-06-01 . The Y-type Brown Dwarfs: Estimates of Mass and Age from New Astrometry, Homogenized Photometry, and Near-infrared Spectroscopy . The Astrophysical Journal . 842 . 2 . 118 . 10.3847/1538-4357/aa6fb5 . 1704.03573 . 2017ApJ...842..118L . 119249195 . 0004-637X . free .
132. Pierre . Maxted . Ralf . Napiwotzki . Paul . Dobbie . Matt . Burleigh . A Sub-Stellar Jonah – Brown Dwarf Survives Being Swallowed . European Southern Observatory . en . 2019-12-11 .
133. Casewell . Sarah L. . Braker . Ian P. . Parsons . Steven G. . Hermes . James J. . Burleigh . Matthew R. . Belardi . Claudia . Chaushev . Alexander . Finch . Nicolle L. . Roy . Mervyn . Littlefair . Stuart P. . Goad . Mike . Dennihy . Erik . 31 January 2018 . The first sub-70 min non-interacting WD–BD system: EPIC212235321 . Monthly Notices of the Royal Astronomical Society . en . 476 . 1 . 1405–1411 . 10.1093/mnras/sty245 . free . 0035-8711 . 2018MNRAS.476.1405C . 1801.07773 . 55776991 .
134. Longstaff . Emma S. . Casewell . Sarah L. . Wynn . Graham A. . Maxted . Pierre F. L. . Helling . Christiane . 2017-10-21 . Emission lines in the atmosphere of the irradiated brown dwarf WD0137−349B . Monthly Notices of the Royal Astronomical Society . en . 471 . 2 . 1728–1736 . 1707.05793 . 10.1093/mnras/stx1786 . free . 0035-8711 . 2017MNRAS.471.1728L . 29792989 .
135. Grether . Daniel . Lineweaver . Charles H. . April 2006 . How Dry is the Brown Dwarf Desert? Quantifying the Relative Number of Planets, Brown Dwarfs, and Stellar Companions around Nearby Sun-like Stars . The Astrophysical Journal . en . 640 . 2 . 1051–1062 . 10.1086/500161 . astro-ph/0412356 . 2006ApJ...640.1051G . 0004-637X . free .
136. Rappaport . Saul A. . Vanderburg . Andrew . Nelson . Lorne . Gary . Bruce L. . Kaye . Thomas G. . Kalomeni . Belinda . Howell . Steve B. . Thorstensen . John R. . Lachapelle . François-René . Lundy . Matthew . St-Antoine . Jonathan . 2017-10-11 . WD 1202-024: the shortest-period pre-cataclysmic variable . Monthly Notices of the Royal Astronomical Society . en . 471 . 1 . 948–961 . 1705.05863 . 10.1093/mnras/stx1611 . free . 0035-8711 . 2017MNRAS.471..948R . 119349942 .
137. Neustroev . Vitaly V. . Mäntynen . Iikka . 2023-08-01 . A brown dwarf donor and an optically thin accretion disc with a complex stream impact region in the period-bouncer candidate BW Sculptoris . Monthly Notices of the Royal Astronomical Society . 523 . 4 . 6114–6137 . 10.1093/mnras/stad1730 . 2212.03264 . 2023MNRAS.523.6114N . 0035-8711. free .
138. Kato . Taichi . 2015-12-01 . WZ Sge-type dwarf novae . Publications of the Astronomical Society of Japan . 67 . 6 . 108 . 10.1093/pasj/psv077 . 1507.07659 . 2015PASJ...67..108K . 0004-6264. free .
139. Web site: Nicolás . Lira . Charles E. . Blue . Calum . Turner . Masaaki . Hiramatsu . When Is a Nova Not a 'Nova'? When a White Dwarf and a Brown Dwarf Collide . ALMA Observatory . dead . https://web.archive.org/web/20191022055806/https://www.almaobservatory.org/en/press-release/when-is-a-nova-not-a-nova-when-a-white-dwarf-and-a-brown-dwarf-collide/ . 2019-10-22 . 2019-11-12 .
140. Eyres . Stewart P. S. . Evans . Aneurin . Zijlstra . Albert . Avison . Adam . Gehrz . Robert D. . Hajduk . Marcin. Sumner Starrfield . Starrfield . Sumner . Mohamed . Shazrene . Woodward . Charles E. . Wagner . R. Mark . 2018-12-21 . ALMA reveals the aftermath of a white dwarf–brown dwarf merger in CK Vulpeculae . Monthly Notices of the Royal Astronomical Society . en . 481 . 4 . 4931–4939 . 1809.05849 . 10.1093/mnras/sty2554 . free . 2018MNRAS.481.4931E . 119462149 . 0035-8711 .
141. Swihart . Samuel J. . Strader . Jay . Chomiuk . Laura . Aydi . Elias . Sokolovsky . Kirill V. . Ray . Paul S. . Kerr . Matthew . 2022-12-01 . A New Flaring Black Widow Candidate and Demographics of Black Widow Millisecond Pulsars in the Galactic Field . The Astrophysical Journal . 941 . 2 . 199 . 10.3847/1538-4357/aca2ac . free . 2210.16295 . 2022ApJ...941..199S . 0004-637X.
142. Dániel . Apai . Ilaria . Pascucci. Ilaria Pascucci . Jeroen . Bouwman . Antonella . Natta . Henning . Thomas . Dullemond . Cornelis P. . 2005 . The Onset of Planet Formation in Brown Dwarf Disks . Science . 310 . 5749 . 834–6 . astro-ph/0511420 . 2005Sci...310..834A . 10.1126/science.1118042 . 16239438 . 5181947 .
143. Riaz . Basmah . Machida . Masahiro N. . Stamatellos . Dimitris . July 2019 . ALMA reveals a pseudo-disc in a proto-brown dwarf . Monthly Notices of the Royal Astronomical Society . en . 486 . 3 . 4114–4129 . 10.1093/mnras/stz1032 . free . 1904.06418 . 2019MNRAS.486.4114R . 119286540 . 0035-8711 .
144. Web site: Basmah . Riaz . Joan . Najita . Punching Above Its Weight, a Brown Dwarf Launches a Parsec-Scale Jet . National Optical Astronomy Observatory . 2020-02-18 . 2020-02-18 . https://web.archive.org/web/20200218195420/https://www.noao.edu/news/2017/pr1701.php . dead .
145. Riaz . Basmah . Briceño . Cesar . Whelan . Emma T. . Heathcote . Stephen . July 2017 . First Large-scale Herbig-Haro Jet Driven by a Proto-brown Dwarf . Astrophysical Journal . en . 844 . 1 . 47 . 10.3847/1538-4357/aa70e8 . 1705.01170 . 2017ApJ...844...47R . 119080074 . 0004-637X . free .
146. Burrows . Adam . Hubbard . William B. . Lunine . Jonathan I. . Liebert . James . 2011 . Tidal evolution of planets around brown dwarfs . Astronomy & Astrophysics . 535 . A94 . 1109.2906 . 2011A&A...535A..94B . 10.1051/0004-6361/201117734 . 118532416 .
147. [David C. Jewitt|Jewitt, David C.]
148. Web site: Our New Paper: Discovery of Nearby Young Brown Dwarf Disk!. Schutte. Maria. 2020-08-12. DiskDetective.org. 2023-09-23.
149. Schutte . Maria C. . Lawson . Kellen D. . Wisniewski . John P. . Kuchner . Marc J. . Silverberg . Steven M. . Faherty . Jacqueline K. . Gagliuffi . Daniella C. Bardalez . Kiman . Rocio . Gagné . Jonathan . Meisner . Aaron . Schneider . Adam C. . Bans . Alissa S. . Debes . John H. . Kovacevic . Natalie . Bosch . Milton K.D. . Luca . Hugo A. Durantini . Holden . Jonathan . Hyogo . Michiharu . 2020-08-04 . Discovery of a Nearby Young Brown Dwarf Disk . The Astrophysical Journal . 160 . 4 . 156 . 10.3847/1538-3881/abaccd . 2007.15735v2 . 2020AJ....160..156S . 220920317 . 1538-3881 . free .
150. Rilinger . Anneliese M. . Espaillat . Catherine C.. Catherine Espaillat . 2021-11-01 . Disk Masses and Dust Evolution of Protoplanetary Disks around Brown Dwarfs . The Astrophysical Journal . 921 . 2 . 182 . 10.3847/1538-4357/ac09e5 . 2106.05247 . 2021ApJ...921..182R . 235377000 . 0004-637X . free .
151. Ricci . L. . Testi . L. . Natta . A. . Scholz . A. . de Gregorio-Monsalvo . I. . Isella . A. . 2014-08-01 . Brown Dwarf Disks with ALMA . The Astrophysical Journal . 791 . 1 . 20 . 10.1088/0004-637X/791/1/20 . 1406.0635 . 2014ApJ...791...20R . 13180928 . 0004-637X.
152. Boucher . Anne . Lafrenière . David . Gagné . Jonathan . Malo . Lison . Faherty . Jacqueline K. . Doyon . René . Chen . Christine H. . 2016-11-01 . BANYAN. VIII. New Low-mass Stars and Brown Dwarfs with Candidate Circumstellar Disks . The Astrophysical Journal . 832 . 1 . 50 . 10.3847/0004-637X/832/1/50 . 1608.08259 . 2016ApJ...832...50B . 119017727 . 0004-637X . free .
153. Silverberg . Steven M. . Wisniewski . John P. . Kuchner . Marc J. . Lawson . Kellen D. . Bans . Alissa S. . Debes . John H. . Biggs . Joseph R. . Bosch . Milton K. D. . Doll . Katharina . Luca . Hugo A. Durantini . Enachioaie . Alexandru . Hamilton . Joshua . Holden . Jonathan . Hyogo . Michiharu . 2020-02-01 . Peter Pan Disks: Long-lived Accretion Disks Around Young M Stars . The Astrophysical Journal . 890 . 2 . 106 . 10.3847/1538-4357/ab68e6 . 2001.05030 . 2020ApJ...890..106S . 210718358 . 0004-637X . free .
154. Luhman . Kevin L. . Adame . Lucía . d'Alessio . Paola . Calvet . Nuria. Nuria Calvet . Hartmann . Lee . Megeath . S. T. . Fazio . G. G. . 2005 . Discovery of a Planetary-Mass Brown Dwarf with a Circumstellar Disk . The Astrophysical Journal . 635 . 1 . L93–L96 . astro-ph/0511807 . 2005ApJ...635L..93L . 10.1086/498868 . 11685964 .
155. Lecavelier des Etangs . A. . Lissauer . Jack J. . 2022-06-01 . The IAU working definition of an exoplanet . New Astronomy Reviews . 94 . 101641 . 10.1016/j.newar.2022.101641 . 2203.09520 . 2022NewAR..9401641L . 247065421 . 1387-6473.
156. Joergens . Viki . Müller . André . 16–20 MJup Radial Velocity Companion Orbiting the Brown Dwarf Candidate Cha Hα 8 . The Astrophysical Journal . 2007 . 666 . 2 . L113–L116 . 10.1086/521825 . 2007ApJ...666L.113J . 0707.3744. 119140521 .
157. Joergens . Viki . Müller . André . Reffert . Sabine . Improved radial velocity orbit of the young binary brown dwarf candidate Cha Hα 8 . Astronomy and Astrophysics . 2010 . 521 . A24 . A24 . 10.1051/0004-6361/201014853 . 2010A&A...521A..24J . 1006.2383. 54989533 .
158. Bennet . David P. . Ian A. . Bond . Andrzej . Udalski . Takahiro . Sumi . Fumio . Abe . Akihiko . Fukui . Kei . Furusawa . John B. . Hearnshaw . Sarah . Holderness . Yoshitaka . Itow . Koki . Kamiya . Aarno V. . Korpela . Pamela M. . Kilmartin . Wei . Lin . Cho Hong . Ling . Kimiaki . Masuda . Yutaka . Matsubara . Noriyuki . Miyake . Yasushi . Muraki . Maiko . Nagaya . Teppei . Okumura . Kouji . Ohnishi . Yvette C. . Perrott . Nicholas J. . Rattenbury . Takashi . Sako . Toshiharu . Saito . S. . Sato . Ljiljana . Skuljan . Denis J. . Sullivan . Winston L. . Sweatman . Paul J. . Tristram . Philip C. M. . Yock . Marcin . Kubiak . Michał K. . Szymański . Grzegorz . Pietrzyński . Igor . Soszyński . O. . Szewczyk . Łukasz . Wyrzykowski . Krzysztof . Ulaczyk . Virginie . Batista . Jean-Philippe . Beaulieu . Stéphane . Brillant . Arnaud . Cassan . Pascal . Fouqué . Pierre . Kervella . Daniel . Kubas . Jean-Baptiste . Marquette . 0806.0025 . A Low-Mass Planet with a Possible Sub-Stellar-Mass Host in Microlensing Event MOA-2007-BLG-192 . The Astrophysical Journal . 30 May 2008 . 684 . 1 . 663–683 . 10.1086/589940 . 2008ApJ...684..663B . 14467194 .
159. 1311.1228 . Burrows . Adam . The Atomic and Molecular Content of Disks Around Very Low-mass Stars and Brown Dwarfs . The Astrophysical Journal . 779 . 2 . 178 . Hubbard . William B. . Lunine . Jonathan I. . Liebert . James . 2013 . 10.1088/0004-637X/779/2/178 . 2013ApJ...779..178P . 119001471 .
160. He . Matthias Y. . Triaud . Amaury H. M. J. . Gillon . Michaël . January 2017 . First limits on the occurrence rate of short-period planets orbiting brown dwarfs . Monthly Notices of the Royal Astronomical Society . 464 . 3 . 2687–2697 . 1609.05053 . 2017MNRAS.464.2687H . 10.1093/mnras/stw2391 . free . 53692008 .
161. Limbach . Mary Anne . Vos . Johanna M. . Winn . Joshua N. . Heller . René . Mason . Jeffrey C. . Schneider . Adam C. . Dai . Fei . 2021-09-01 . On the Detection of Exomoons Transiting Isolated Planetary-mass Objects . The Astrophysical Journal . 918 . 2 . L25 . 2108.08323 . 2021ApJ...918L..25L . 10.3847/2041-8213/ac1e2d . 0004-637X . free.
162. Vos . Johanna M. . Allers . Katelyn N. . Biller . Beth A. . 2017-06-01 . The Viewing Geometry of Brown Dwarfs Influences Their Observed Colors and Variability Amplitudes . The Astrophysical Journal . 842 . 2 . 78 . 1705.06045 . 2017ApJ...842...78V . 10.3847/1538-4357/aa73cf . free . 0004-637X.
163. 2013AsBio..13..279B . 1211.6467 . 10.1089/ast.2012.0867 . Habitable Planets Around White and Brown Dwarfs: The Perils of a Cooling Primary . 2011 . Barnes . Rory . Heller . René . Astrobiology . 13 . 3 . 279–291 . 23537137 . 3612282.
164. Web site: 2 August 2011 . Scientists today no longer think an object like Nemesis could exist . NASA Ask An Astrobiologist . David . Morrison . David Morrison (astrophysicist) . https://archive.today/20121213101422/http://astrobiology2.arc.nasa.gov/ask-an-astrobiologist/question/?id=16790 . dead . 13 December 2012 . 2011-10-22 .
165. Comerón . F. . Neuhäuser . R. . Kaas . A. A. . 2000-07-01 . Probing the brown dwarf population of the Chamaeleon I star forming region . Astronomy and Astrophysics . 359 . 269–288 . 2000A&A...359..269C . 0004-6361.
166. Whelan. Emma T.. Ray. Thomas P.. Bacciotti. Francesca. Natta. Antonella. Testi. Leonardo. Randich. Sofia. June 2005. A resolved outflow of matter from a brown dwarf. Nature. en. 435. 7042. 652–654. 10.1038/nature03598. 15931217. astro-ph/0506485. 2005Natur.435..652W. 4415442. 0028-0836.
167. astro-ph/9908015 . [astro-ph/9908015&#93; PPl 15: The First Brown Dwarf Spectroscopic Binary |year=1999 |last1=Basri |first1=Gibor |last2=Martín |first2=Eduardo L. |doi=10.1086/301079 |journal=The Astronomical Journal |volume=118 |issue=5 |pages=2460–2465 |bibcode=1999AJ....118.2460B|s2cid=17662168 ].
168. 0704.3106 . A Surprising Reversal of Temperatures in the Brown-Dwarf Eclipsing Binary 2MASS J05352184-0546085 . 2007 . Stassun . Keivan G. . Mathieu . Robert D. . Valenti . Jeff A. . 10.1086/519231 . The Astrophysical Journal . 664 . 2 . 1154–1166 . 2007ApJ...664.1154S. 15144741 .
169. Ralf-Dieter . Scholz . Mark . McCaughrean . eso0303 – Discovery of Nearest Known Brown Dwarf . 2003-01-13 . European Southern Observatory . 2013-03-16 . dead . https://web.archive.org/web/20081013074256/http://www.eso.org/outreach/press-rel/pr-2003/pr-01-03.html . October 13, 2008.
170. astro-ph/0410226 . Burrows . Adam . A possible third component in the L dwarf binary system DENIS-P J020529.0-115925 discovered with the Hubble Space Telescope . The Astronomical Journal . 129 . 1 . 511–517 . Hubbard . William B. . Lunine . Jonathan I. . Liebert . James . 2004 . 10.1086/426559 . 2005AJ....129..511B . 119336794 .
171. Burgasser . Adam J. . J. Davy . Kirkpatrick . Adam . Burrows . James . Liebert . I. Neill . Reid . John E. . Gizis . Mark R. . McGovern . Lisa . Prato . Ian S. . McLean . 2003 . The First Substellar Subdwarf? Discovery of a Metal-Poor L Dwarf with Halo Kinematics . The Astrophysical Journal . 592 . 2 . 1186–1192 . 10.1086/375813 . astro-ph/0304174 . 2003ApJ...592.1186B . 11895472 .
172. Burningham . Ben . Pinfield . David J. . Leggett . Sandy K. . Tamura . Motohide . Lucas . Philip W. . Homeier . Derek . Day-Jones . Avril . Jones . Hugh R. A. . Clarke . J. R. A. . Ishii . Miki . Kuzuhara . Masayuki . Lodieu . Nicolas . Zapatero-Osorio . María Rosa . Venemans . Bram Pieter . Mortlock . Daniel J. . Barrado y Navascués . David . Martín . Eduardo L. . Magazzù . Antonio . Exploring the substellar temperature regime down to ~550K . 2008 . 10.1111/j.1365-2966.2008.13885.x . Monthly Notices of the Royal Astronomical Society . 391 . 1 . 320–333 . free . 0806.0067 . 2008MNRAS.391..320B . 1438322 .
173. 1404.4682 . Wolszczan . Alexander . Route . Matthew . Timing Analysis of the Periodic Radio and Optical Brightness Variations of the Ultracool Dwarf, TVLM 513-46546 . The Astrophysical Journal . 788 . 1 . 23 . 2014 . 10.1088/0004-637X/788/1/23 . 2014ApJ...788...23W . 119114679 .
174. Survival of a brown dwarf after engulfment by a red giant star . 10.1038/nature04987 . Maxted . Pierre F. L. . Napiwotzki . Ralf . Dobbie . Paul D. . Burleigh . Matthew R. . 2006 . Nature . 442 . 543–5 . 16885979 . 7102 . astro-ph/0608054 . 2006Natur.442..543M . https://web.archive.org/web/20210427120858/https://cds.cern.ch/record/976227 . dead . 2021-04-27 . Submitted manuscript . 2299/1227 . 4368344 .
175. Mace . Gregory N. . Mann . Andrew W. . Skiff . Brian A. . Sneden . Christopher . Kirkpatrick . J. Davy . Schneider . Adam C. . Kidder . Benjamin . Gosnell . Natalie M. . Kim . Hwihyun . Mulligan . Brian W. . Prato . L. . Jaffe . Daniel . 2018-02-01 . Wolf 1130: A Nearby Triple System Containing a Cool, Ultramassive White Dwarf . The Astrophysical Journal . 854 . 2 . 145 . 10.3847/1538-4357/aaa8dd . 1802.04803 . 2018ApJ...854..145M . 56431008 . 0004-637X . free .
176. Rothermich . Austin . Faherty . Jacqueline K. . Jackie Faherty . Bardalez-Gagliuffi . Daniella . Schneider . Adam C. . Kirkpatrick . J. Davy . J. Davy Kirkpatrick . Meisner . Aaron M. . Burgasser . Adam J. . Kuchner . Marc . Marc Kuchner . Allers . Katelyn . Gagné . Jonathan . Caselden . Dan . Calamari . Emily . Popinchalk . Mark . Gerasimov . Roman . Aganze . Christian . 7 Mar 2024 . 89 New Ultracool Dwarf Co-Moving Companions Identified With The Backyard Worlds: Planet 9 Citizen Science Project . AJ . 2403.04592 . Softich . Emma . Hsu . Chin-Chun . Karpoor . Preethi . Theissen . Christopher A. . Rees . Jon . Cecilio-Flores-Elie . Rosario . Cushing . Michael C. . Marocco . Federico . Casewell . Sarah . Hamlet . Les . Allen . Michaela B. . Beaulieu . Paul . Guillaume . Colin . Jean Marc . Gantier . Leopold . Gramaize . Peter . Jałowiczor . Martin . Kabatnik . Frank . Kiwi . David W. . Martin . Billy . Pendrill . Ben . Pumphrey . Arttu . Sainio . Jörg . Schümann . Nikolaj . Stevnbak . Guoyou . Sun . Christopher . Tanner . Vinod . Thakur . Melina . Thévenot . Zbigniew . Wedracki. 167 . 6 . 253 . 10.3847/1538-3881/ad324e . free . 2024AJ....167..253R .
177. Levine . Joanna L. . Steinhauer . Aaron . Elston . Richard J. . Lada . Elizabeth A. . 2006-08-01 . Low-Mass Stars and Brown Dwarfs in NGC 2024: Constraints on the Substellar Mass Function . The Astrophysical Journal . 646 . 2 . 1215–1229 . 10.1086/504964 . astro-ph/0604315 . 2006ApJ...646.1215L . 118955538 . 0004-637X . Table 3: FLMN_J0541328-0151271.
178. Primeval very low-mass stars and brown dwarfs – II. The most metal-poor substellar object . Monthly Notices of the Royal Astronomical Society . 468 . 1 . 261 . 2017-06-11 . 1702.02001 . Zhang . ZengHua . Homeier . Derek . Pinfield . David J. . Lodieu . Nicolas . Jones . Hugh R. A. . Pavlenko . Yakiv V. . 10.1093/mnras/stx350. free . 2017MNRAS.468..261Z . 54847595 .
179. 2206.13097 . 10.1051/0004-6361/202243516 . Physical properties and trigonometric distance of the peculiar dwarf WISE J181005.5−101002.3 . 2022 . Lodieu . N. . Zapatero Osorio . M. R. . Martín . E. L. . Rebolo López . R. . Gauza . B. . Astronomy & Astrophysics . 663 . A84 . 2022A&A...663A..84L .
180. Weather on Other Worlds. V. The Three Most Rapidly Rotating Ultra-cool Dwarfs . Megan E. . Tannock . Stanimir . Metchev . Aren . Heinze . Paulo A. . Miles-Páez . Jonathan . Gagné . Adam J. . Burgasser . Mark S. . Marley . Dániel . Apai . Genaro . Suárez . Peter . Plavchan. The Astronomical Journal . March 2021 . 161 . 5 . 224 . 10.3847/1538-3881/abeb67 . 2103.01990 . 2021AJ....161..224T . 232105126 . free .
181. Encyclopedia: The Extrasolar Planet Encyclopaedia — KMT-2016-BLG-2142 b . . 2021-01-12 .
182. Jung . Youn Kil . Hwang . Kyu-Ha . Ryu . Yoon-Hyun . Gould . Andrew . Han . Cheongho . Yee . Jennifer C. . Albrow . Michael D. . Chung . Sun-Ju . Shin . In-Gu . Shvartzvald . Yossi . Zang . Weicheng . Cha . Sang-Mok . Kim . Dong-Jin . Kim . Hyoun-Woo . Kim . Seung-Lee . 2018-11-01 . KMT-2016-BLG-1820 and KMT-2016-BLG-2142: Two Microlensing Binaries Composed of Planetary-mass Companions and Very-low-mass Primaries . The Astronomical Journal . 156 . 5 . 208 . 10.3847/1538-3881/aae319 . free . 1805.09983 . 2018AJ....156..208J . 0004-6256.
183. Sanghi . Aniket . Liu . Michael C. . Best . William M. J. . Dupuy . Trent J. . Siverd . Robert J. . Zhang . Zhoujian . Hurt . Spencer A. . Magnier . Eugene A. . Aller . Kimberly M. . Deacon. Niall R. . Table of Ultracool Fundamental Properties . Zenodo. 2023 . 10.5281/zenodo.10086810 .
184. 2306.15219 . Rose . Kovi . Pritchard . Joshua . Murphy . Tara . Caleb . Manisha . Manisha Caleb. Dobie . Dougal . Driessen . Laura . Duchesne . Stefan . Kaplan . David . Lenc . Emil . Wang . Ziteng . Periodic Radio Emission from the T8 Dwarf WISE J062309.94−045624.6 . The Astrophysical Journal Letters. 2023 . 951 . 2 . L43 . 10.3847/2041-8213/ace188 . 2023ApJ...951L..43R . 259262475 . free .
185. Web site: Transiting Brown Dwarfs from TESS 2 . 2013-03-16 . . 24 June 2020 . AAS Nova .