Equinox J2000.0]] (ICRS)
|Right ascension||18h 08m 20.02s|
|Declination||−51° 04′ 37.8″|
|Apparent magnitude (V)||11.9|
|Evolutionary stage||Subgiant / Red dwarf|
|Proper motion (μ)|| RA: −5.672 mas/yr |
Dec.: −12.643 mas/yr
|Parallax (π)||1.6775 ± 0.0397 mas|
|Distance||1,950 ly |
|Mass||0.7599 ± 0.0001 M☉|
|Surface gravity (log g)||3.0 cgs|
|Temperature||5,440 ± 100 K|
|Metallicity [Fe/H]||-4.1 dex|
Gaia DR2 6702907209758894848
2MASS J18082002−5104378 (abbreviated J1808−5104) is an ultra metal-poor (UMP) binary star system, in the constellation Ara, about 1,950 ly (600 pc) from Earth, and is a single-lined spectroscopic binary (SB1). It is one of the oldest stars in the universe, about 13.53 billion years old, possibly one of the first stars, a star made almost entirely of materials released from the Big Bang. A tiny unseen companion, a low-mass UMP star, is particularly unusual.
J1808−5104 is an ultra metal-poor (UMP) star, one that has a metallicity [Fe/H] less than −4, 1⁄10,000th of the levels in the Sun. It is a single-lined spectroscopic binary, with radial velocity variations in its spectral absorption lines interpreted as orbital motion of the visible star. The companion is invisible, but inferred from the orbit.
J1808−5104 is the brightest UMP star, as a binary system, known, and is part of the "thin disk" of the Milky Way, the part of the galaxy in which the Sun is located, but unusual for such a metal-poor and old star. At 13.53 Gyr, the star is the oldest known thin-disk star, and several billion years older than most estimates for the age of the Milky Way's thin disk.
The secondary unseen companion, 2MASS J18082002−5104378 B, thought to be a red dwarf, has an orbital period P = 34.757+0.010
−0.010 days and a mass of 0.14 M☉. It is the first low-mass UMP star to be discovered, and one of the oldest stars in the universe, about 13.53 billion years old. It is possibly one of the first stars, a star made almost entirely of materials released from the Big Bang.
- Schlaufman, Kevin C.; Thompson, Ian B.; Casey, Andrew R. (5 November 2018). "An ultra metal-poor star near the hydrogen-burning limit". The Astrophysical Journal 867 (2): 98. doi:10.3847/1538-4357/aadd97. Bibcode: 2018ApJ...867...98S.
- "Finding the constellation which contains given sky coordinates". 2018. http://djm.cc/constellation.html.
- Meléndez, Jorge; Placco, Vinicius M.; Tucci-Maia, Marcelo; Ramírez, Iván; Li, Ting S.; Perez, Gabriel (2016). "2MASS J18082002-5104378: The brightest (V = 11.9) ultra metal-poor star". Astronomy and Astrophysics 585: L5. doi:10.1051/0004-6361/201527456. Bibcode: 2016A&A...585L...5M.
- Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- "One of Milky Way's oldest stars discovered". 6 November 2018. http://www.sci-news.com/astronomy/ultra-metal-poor-star-06577.html.
- Crockett, Christopher (12 November 2018). "Puny star might be [a specimen from [the] early universe"]. https://www.skyandtelescope.com/astronomy-news/puny-star-might-be-specimen-from-early-universe/.
- Williams, Matt (9 November 2018). "Ancient star found that's only slightly younger than the universe itself". https://www.universetoday.com/140468/ancient-star-found-thats-only-slightly-younger-than-the-universe-itself/.
- Ezzeddine, Rana; Frevbel, Anna (27 September 2018). "Revisiting the iron abundance in the hyper iron-poor star HE 1327−2326 with UV COS/HST data". The Astrophysical Journal 863 (2): 168. doi:10.3847/1538-4357/aad3cb. Bibcode: 2018ApJ...863..168E.
- Rosen, Jill (5 November 2018). "Johns Hopkins scientist finds elusive star with origins close to Big Bang - The newly discovered star's composition indicates that, in a cosmic family tree, it could be as little as one generation removed from the Big Bang" (Press release). Johns Hopkins University. Retrieved 5 November 2018.
- Wehner, Mike (5 November 2018). "Astronomers spot one of the oldest stars ever". https://bgr.com/2018/11/05/oldest-star-ever-astronomy-milky-way/.
- "A tiny old star has a huge impact". Gemini Observatory. 5 November 2018. http://spaceref.com/astronomy/a-tiny-old-star-has-a-huge-impact.html.
- "Johns Hopkins scientist finds elusive star with origins close to Big Bang" (Press release). Johns Hopkins University. 5 November 2018. Retrieved 5 November 2018 – via EurekAlert!.
- Starr, Michelle (5 November 2018). "Astronomers have detected one of the oldest stars in the entire universe". https://www.sciencealert.com/tiny-ancient-metal-poor-star-in-the-milky-way-could-be-one-of-the-oldest-in-the-universe.
- Irving, Michael (5 November 2018). "13.5 billion year old star was born just after the Big Bang - and it's in our neighborhood". https://newatlas.com/ancient-star-one-generation-big-bang/57089/.
- Malewar, Amit (5 November 2018). "Johns Hopkins scientists may have found one of the universe's oldest stars - One of the universe's oldest stars". https://www.techexplorist.com/johns-hopkins-scientists-may-have-found-one-of-the-universes-oldest-stars/18215/.
- "2MASS J18082002−5104378". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=2MASS+J18082002%E2%88%925104378.
- "2MASS J18082002−5104378 B". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=2MASS+J18082002%E2%88%925104378+B.
- on YouTube (5 November 2018; Johns Hopkins University)
Original source: https://en.wikipedia.org/wiki/ 2MASS J18082002−5104378. Read more