J band (infrared) explained

In infrared astronomy, the J band refers to an atmospheric transmission window (1.1 to 1.4 μm) centred on 1.25 micrometres (in the near-infrared).

Betelgeuse is the brightest near-IR source in the sky with a J band magnitude of −2.99.[1] The next brightest stars in the J band are Antares (−2.7), R Doradus (−2.6), Arcturus (−2.2), and Aldebaran (−2.1).[2] In the J band Sirius is the 9th brightest star.

The J band is a frequent source of ground based observations since the wavelengths it covers pass through clouds and other atmospheric gasses.[3] The waveband does however suffer from contamination by water vapor lines and hydroxide emission lines leading to relatively high photometric error.[4]

It can be used to scrutinize the photosphere of giant and supergiant stars while mostly avoiding opacities from molecular bands and also has access to the 1080 nm He I line which is useful in the study of circumstellar disk interactions around T-Tauri stars.[5] J, H and K-band spectroscopy is also commonly used to observe and research brown dwarfs[6] and directly imaged exoplanets.[7]

Notes and References

  1. Web site: 2009-09-07 . Very Bright Stars in the 2MASS Point Source Catalog (PSC) . The Two Micron All Sky Survey at IPAC . R. Cutri and M. Skrutskie . 2011-12-28.
  2. Web site: Simbad object query:Jmag<-2 & Vmag>-9 . SIMBAD Astronomical Database . 2012-08-22.
  3. Web site: Infrared Astronomy Optical Filters . 2023-04-01 . www.andovercorp.com.
  4. Simons . D. A. . Tokunaga . A. T. . February 2002 . The Mauna Kea Observatories Near-Infrared Filter Set. I: Defining Optimal 1-5 $\mu$m Bandpasses . Publications of the Astronomical Society of the Pacific . 114 . 792 . 169–179 . 10.1086/338544 . astro-ph/0110594 . 7880289 . 0004-6280.
  5. Book: Pedretti . Ettore . Piacentini . S. . Corrielli . G. . Osellame . Roberto . Minardi . Stefano . Optical and Infrared Interferometry and Imaging VI . A six-apertures discrete beam combiners for J-band interferometry . Peter G. . Michelle J. . Antoine . Tuthill . Creech-Eakman . Mérand . 2018-07-09 . https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10701/1070116/A-six-apertures-discrete-beam-combiners-for-J-band-interferometry/10.1117/12.2312033.full . SPIE . 10701 . 316–325 . 10.1117/12.2312033. 1809.01260 . 2018SPIE10701E..16P . 9781510619555 . 119458175 .
  6. 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.
  7. Oppenheimer . B. R. . 2013 . Reconnaissance of the HR 8799 Exosolar System I: Near IR Spectroscopy . . . 768 . 1 . 24 . 1303.2627 . 2013ApJ...768...24O . 10.1088/0004-637X/768/1/24 . 7173368.

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