Astronomy:2MASS J18082002−5104378

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Short description: One of the oldest stars in the universe in the constellation Ara
2MASS J18082002−5104378[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Ara[2]
Right ascension  18h 08m 20.02s
Declination −51° 04′ 37.8″
Apparent magnitude (V) 11.9[3]
Characteristics
Evolutionary stage Subgiant / Red dwarf
Astrometry
Proper motion (μ) RA: −5.672[4] mas/yr
Dec.: −12.643[4] mas/yr
Parallax (π)1.6775 ± 0.0397[4] mas
Distance1,950[5][6][7] ly
(600 pc)
Details
A
Mass0.7599 ± 0.0001[1] M☉
Radius2.44[4] R☉
Luminosity5.311[4] L☉
Surface gravity (log g)3.0[3] cgs
Temperature5,440 ± 100[3] K
Metallicity [Fe/H]-4.1[3] dex
Age13.535±0.002[1] Gyr
B
Mass0.14+0.06
−0.01[1] M☉
Age13.535±0.002[1] Gyr
Other designations
Gaia DR2 6702907209758894848[5]
Database references
SIMBADdata

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)[5][6][7] from Earth, and is a single-lined spectroscopic binary (SB1). It is one of the oldest stars known, 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.

System

J1808−5104 is an ultra metal-poor (UMP) star, one that has a logarithmic metallicity [Fe/H] less than −4, or 1/ 10,000 th of the levels in the Sun.[8] 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.[1]

J1808−5104 is the brightest UMP star, as a binary system, known,[8] 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.[9] 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.[1]

Primary star

The primary component of the binary star system, 2MASS J18082002−5104378 A, is a subgiant, cooler than the Sun, but larger and more luminous.[3]

Secondary star

The secondary unseen companion, 2MASS J18082002−5104378 B, thought to be a red dwarf,[5] has an orbital period P = 34.757+0.010
−0.010 days and a mass of 0.14 M☉.[1] 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.[5] It is possibly one of the first stars, a star made almost entirely of materials released from the Big Bang.[1][10][11][9][12][13][14][15]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 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. 
  2. ↑ "Finding the constellation which contains given sky coordinates". 2018. http://djm.cc/constellation.html. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 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. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 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.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 "One of Milky Way's oldest stars discovered". 6 November 2018. http://www.sci-news.com/astronomy/ultra-metal-poor-star-06577.html. 
  6. ↑ 6.0 6.1 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/. 
  7. ↑ 7.0 7.1 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/. 
  8. ↑ 8.0 8.1 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. 
  9. ↑ 9.0 9.1 Rosen, Jill (5 November 2018). "Johns Hopkins scientist finds elusive star with origins close to Big Bang" (Press release). Johns Hopkins University. Retrieved 5 November 2018. 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.
  10. ↑ 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/. 
  11. ↑ "A tiny old star has a huge impact". SpaceRef.com (Press release). Gemini Observatory. 5 November 2018. Retrieved 6 November 2018.
  12. ↑ "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!.
  13. ↑ 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. 
  14. ↑ 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/. 
  15. ↑ 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/. 

External links

Coordinates: Sky map 18h 08m 20.02s, −51° 04′ 37.8″



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