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2MASS J18082002−5104378

天球赤道座標星圖 18h 08m 20.02s, −51° 04′ 37.8″
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2MASS J18082002−5104378[1]
觀測資料
曆元 J2000
星座 天壇座[2]
星官
赤經 18h 08m 20.02s
赤緯 −51° 04′ 37.8″
視星等(V) 11.9[3]
特性
演化阶段次巨星 / 紅矮星
天体测定
自行 (μ) 赤经:−5.672[4] mas/yr
赤纬:−12.643[4] mas/yr
视差 (π)1.6775 ± 0.0397[4] mas
距离1,950[5][6][7] ly
(600 pc)
詳細資料
A
質量0.7599 ± 0.0001[1] M
半徑2.44[4] R
表面重力 (log g)3.0[3]
亮度5.311[4] L
溫度5,440 ± 100[3] K
金属量 [Fe/H]-4.1[3] dex
年齡13.535±0.002[1] Gyr
B
質量0.14+0.06
−0.01
[1] M
年齡13.535±0.002[1] Gyr
其他命名
Gaia DR2 6702907209758894848[5]
參考資料庫
SIMBAD资料

2MASS J18082002−5104378(縮寫為J1808−5104)是一個超貧金屬(UMP)聯星系統,位於天壇座,距離地球大約1,950 ly(600 pc)[5][6][7],並且是單線光譜聯星(SB1)。它是已知最古老的恆星之一,約有135.3億年的歷史,可能是最早的恆星之一。這顆恆星幾乎完全由宇宙大爆炸釋放的物質組成。一個看不見的微小伴星,一顆低質量的UMP恆星,特別不尋常。

系統

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J1808−5104是一顆超貧金屬(UMP)星,其對數金屬豐度[Fe/H]小於−4,或太陽1/   10,000  的級別[8]。它是一個單線光譜聯星,其光譜吸收線徑向速度變化被解釋為可見恆星的軌道運動。這顆伴星是看不見的,而僅是從軌道上推斷出來的[1]

J1808−5104是已知最亮的聯星系統超貧金屬星[8],是太陽所在星系銀河系薄盤」的一部分,但對於這樣一顆缺乏金屬的古老恆星來說是不尋常的[9]。在13.53 Gyr,這顆恆星是已知最古老的薄盤恆星,比大多數對銀河系薄盤年齡的估計要早幾十億年[1]

主星

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聯星系統的主要組成部分,2MASS J18082002−5104378 A,是一顆比太陽冷,但更大、更亮的次巨星[3]

伴星

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看不見的伴星,2MASS J18082002−5104378 B,被認為是一顆紅矮星 [5]軌道週期 P = 34.757+0.010
−0.010
日和質量為0.14 M[1]。它是第一顆被發現的低質量超貧金屬星,也是宇宙中最古老的恆星之一,約有135.3億年的歷史[5]。它可能是最早的恆星之一,一顆幾乎完全由大爆炸釋放的物質形成的恆星[1][10][11][9][12][13][14][15]

參考資料

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  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. An ultra metal-poor star near the hydrogen-burning limit. The Astrophysical Journal. 5 November 2018, 867 (2): 98. Bibcode:2018ApJ...867...98S. S2CID 54511945. arXiv:1811.00549可免费查阅. doi:10.3847/1538-4357/aadd97可免费查阅. 
  2. ^ Finding the constellation which contains given sky coordinates. DJM.cc. 2018 [5 November 2018]. (原始内容存档于2019-08-15). 
  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. 2MASS J18082002-5104378: The brightest (V = 11.9) ultra metal-poor star. Astronomy and Astrophysics. 2016, 585: L5. Bibcode:2016A&A...585L...5M. S2CID 119240055. arXiv:1601.03462可免费查阅. doi:10.1051/0004-6361/201527456. 
  4. ^ 4.0 4.1 4.2 4.3 4.4 Brown, A. G. A.; Vallenari, A.; Prusti, T.; de Bruijne, J. H. J.; et al. Gaia Data Release 2. Summary of the contents and survey properties. Astronomy & Astrophysics. 2018. Bibcode:2018A&A...616A...1G. arXiv:1804.09365可免费查阅. doi:10.1051/0004-6361/201833051.  VizieR中此天体在盖亚望远镜第二批数据发布的记录
  5. ^ 5.0 5.1 5.2 5.3 5.4 One of Milky Way's oldest stars discovered. SciNews.com. 6 November 2018 [6 November 2018]. (原始内容存档于2018-11-06). 
  6. ^ 6.0 6.1 Crockett, Christopher. Puny star might be [a] specimen from [the] early universe. Sky & Telescope. 12 November 2018 [14 November 2018]. (原始内容存档于2018-11-12). 
  7. ^ 7.0 7.1 Williams, Matt. Ancient star found that's only slightly younger than the universe itself. Universe Today. 9 November 2018 [14 November 2018]. (原始内容存档于2024-01-26). 
  8. ^ 8.0 8.1 Ezzeddine, Rana; Frevbel, Anna. Revisiting the iron abundance in the hyper iron-poor star HE 1327−2326 with UV COS/HST data. The Astrophysical Journal. 27 September 2018, 863 (2): 168. Bibcode:2018ApJ...863..168E. S2CID 118918067. arXiv:1807.06153可免费查阅. doi:10.3847/1538-4357/aad3cb可免费查阅. 
  9. ^ 9.0 9.1 Rosen, Jill. Johns Hopkins scientist finds elusive star with origins close to Big Bang (新闻稿). Johns Hopkins University. 5 November 2018 [5 November 2018]. (原始内容存档于2018-11-06). 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. Astronomers spot one of the oldest stars ever. BGR. 5 November 2018 [5 November 2018]. (原始内容存档于2018-11-06). 
  11. ^ A tiny old star has a huge impact. SpaceRef.com (新闻稿). Gemini Observatory. 5 November 2018 [6 November 2018]. [永久失效連結]
  12. ^ Johns Hopkins scientist finds elusive star with origins close to Big Bang (新闻稿). Johns Hopkins University. 5 November 2018 [5 November 2018]. (原始内容存档于2018-11-06) –通过EurekAlert!. 
  13. ^ Starr, Michelle. Astronomers have detected one of the oldest stars in the entire universe. ScienceAlert.com. 5 November 2018 [5 November 2018]. (原始内容存档于2018-11-05). 
  14. ^ Irving, Michael. 13.5 billion year old star was born just after the Big Bang - and it's in our neighborhood. NewAtlas.com. 5 November 2018 [5 November 2018]. (原始内容存档于2018-11-05). 
  15. ^ Malewar, Amit. Johns Hopkins scientists may have found one of the universe's oldest stars - One of the universe's oldest stars. TechExplorist.com. 5 November 2018 [5 November 2018]. (原始内容存档于2018-11-05). 

外部連結

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