2MASS J18082002−5104378
| 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[编辑]
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，其光譜吸收線的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[编辑]
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[编辑]
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[编辑]
- ^ 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
. doi:10.3847/1538-4357/aadd97 .
- ^ Finding the constellation which contains given sky coordinates. DJM.cc. 2018 [5 November 2018].
- ^ 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 . doi:10.1051/0004-6361/201527456.
- ^ 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 . 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
- ^ 5.0 5.1 5.2 5.3 5.4 One of Milky Way's oldest stars discovered. SciNews.com. 6 November 2018 [6 November 2018].
- ^ 6.0 6.1 Crockett, Christopher. Puny star might be [a] specimen from [the] early universe. Sky & Telescope. 12 November 2018 [14 November 2018].
- ^ 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].
- ^ 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 . doi:10.3847/1538-4357/aad3cb .
- ^ 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].
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.
- ^ Wehner, Mike. Astronomers spot one of the oldest stars ever. BGR. 5 November 2018 [5 November 2018].
- ^ 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]
- ^ Johns Hopkins scientist finds elusive star with origins close to Big Bang (新闻稿). Johns Hopkins University. 5 November 2018 [5 November 2018] –通过EurekAlert!.
- ^ Starr, Michelle. Astronomers have detected one of the oldest stars in the entire universe. ScienceAlert.com. 5 November 2018 [5 November 2018].
- ^ 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].
- ^ 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].
外部連結[编辑]
- 2MASS J18082002−5104378. SIMBAD. 斯特拉斯堡天文資料中心.
- 2MASS J18082002−5104378 B. SIMBAD. 斯特拉斯堡天文資料中心.
- YouTube上的Video (00:30) – Orbit of newly found 13.5 billion-year-old star (5 November 2018; Johns Hopkins University)
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