Sculptor Dwarf Galaxy Explained

Sculptor Dwarf Elliptical Galaxy
Epoch:J2000
Ra:[1]
Constellation Name:Sculptor
Z:110 ± 1 km/s
Dist Ly:290 ± 30 kly (90 ± 10 kpc)[2] [3]
Type:E
Appmag V:10.1
Size V:39′.8 × 30′.9
Names:Sculptor Dwarf Spheroidal, PGC 3589, MCG-06-03-015, ESO 351-30[4]

The Sculptor Dwarf Galaxy (also known as Sculptor Dwarf Elliptical Galaxy or the Sculptor Dwarf Spheroidal Galaxy, and formerly as the Sculptor System) is a dwarf spheroidal galaxy that is a satellite of the Milky Way. The galaxy lies within the constellation Sculptor. It was discovered in 1937 by American astronomer Harlow Shapley using the 24-inch Bruce refractor at Boyden Observatory.[5] [6] The galaxy is located about 290,000 light-years away from the Solar System. The Sculptor Dwarf contains only 4 percent of the carbon and other heavy elements in our own galaxy, the Milky Way, making it similar to primitive galaxies seen at the edge of the universe.[7]

Metallicity

The metallicity of Sculptor dwarf appears to be broken up into two distinct groups, one with [Fe/H] = −2.3 and the other with [Fe/H] = −1.5.[8] Similar to many of the other Local Group galaxies, the older metal-poor segment appears more extended than the younger metal-rich segment.[9] Using cosmological numerical simulations, it has been recently argued that Sculptor's two distinct stellar populations would be the tell-tale sign of a past merger between Sculptor and another small dwarf galaxy companion.[10]

The Sculptor Dwarf is home to the most metal-poor star outside of the Milky Way, known as AS0039, with a metallicity of [Fe/H] = −4.11. Unlike other known metal-poor stars, it has a low carbon abundance and an unusual ratio of alpha elements, suggesting it may have been formed in the aftermath of a Population III star hypernova.[11]

Measurements

Using both Hubble Space Telescope and Gaia observations 12 years apart, about 100 stars in the galaxy were mapped accurately, and 3D motions of about 10 of those stars enable trajectories to be mapped as well.[12]

Notes and References

  1. Web site: NASA/IPAC Extragalactic Database . Results for PGC 3589 . 2006-12-03.
  2. I. D. Karachentsev . V. E. Karachentseva . W. K. Hutchmeier . D. I. Makarov . A Catalog of Neighboring Galaxies . Astronomical Journal . 2004 . 128 . 4 . 2031–2068 . 2004AJ....127.2031K . 10.1086/382905 . abstract . free .
  3. Karachentsev, I. D.. Kashibadze, O. G. . Masses of the local group and of the M81 group estimated from distortions in the local velocity field . Astrophysics . 2006 . 49 . 1 . 3–18 . 2006Ap.....49....3K . 10.1007/s10511-006-0002-6 . 120973010 .
  4. Book: Stoyan. Ronald. Schurig. Stephan. interstellarum Deep Sky Atlas. Cambridge University Press; Oculum-Verlag GmbH. Erlangen. 2014. 978-1-107-50338-0. 920437579.
  5. Shapley . H. . 1938 . A Stellar System of a New Type . Harvard College Observatory Bulletin . 908 . 1–11 . 1938BHarO.908....1S .
  6. Shapley H . 1938 . Two Stellar Systems of a New Kind . Nature . 142 . 3598. 715–6 . 1938Natur.142..715S . 10.1038/142715b0. 4071472 .
  7. http://newswise.com/articles/view/548031/ Astronomers Detect Dust Around a Primitive Star, Shedding New Light on Universe’s Origins
  8. S.R. Majewski . etal . An Internal Second-Parameter Problem in the Sculptor Dwarf Spheroidal Galaxy . 20 July 1999 . The Astrophysical Journal . 520 . 1 . L33–L36 . astro-ph/9905238 . 1999ApJ...520L..33M . 10.1086/312133 . 14523540 .
  9. van den Bergh . Sidney . Sidney van den Bergh . Updated Information on the Local Group . April 2000 . The Publications of the Astronomical Society of the Pacific . 112 . 770 . 2000PASP..112..529V . 529–536 . 10.1086/316548 . astro-ph/0001040 . 1805423.
  10. Benítez-Llambay. A.. Navarro. J. F.. Abadi. M. G.. Gottlöber. S.. Yepes. G.. Hoffman. Y.. Steinmetz. M.. 2016-02-21. Mergers and the outside-in formation of dwarf spheroidals. Monthly Notices of the Royal Astronomical Society. en. 456. 2. 1185–1194. 10.1093/mnras/stv2722. free . 0035-8711. 10486/684610. free.
  11. 10.3847/2041-8213/ac0dc2. Zero-metallicity Hypernova Uncovered by an Ultra-metal-poor Star in the Sculptor Dwarf Spheroidal Galaxy. Skúladóttir, Ása. Salvadori, Stefania. Amarsi, Anish M.. Tolstoy, Eline. Irwin, Michael J.. Hill, Vanessa. Jablonka, Pascale. Battaglia, Giuseppina. Starkenburg, Else. Massari, Davide. Helmi, Amina. Posti, Lorenzo. The Astrophysical Journal Letters. 2021 . 915. 2. L30. 8. 2106.11592. 2021ApJ...915L..30S. 235593020 . free .
  12. https://www.spacetelescope.org/news/heic1719/ Hubble and Gaia team up to measure 3D stellar motion with record-breaking precision

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Sculptor Dwarf Galaxy".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2024, A B Cryer, All Rights Reserved. Cookie policy.