2MASS J18082002−5104378
| 观测资料 历元 J2000 | |
|---|---|
| 星座 | 天坛座[2] |
| 星官 | |
| 赤经 | 18h 08m 20.02s |
| 赤纬 | −51° 04′ 37.8″ |
| 视星等（V） | 11.9[3] |
| 特性 | |
| 演化阶段 | 次巨星 / 红矮星 |
| 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) |
| 详细资料 | |
| A | |
| 质量 | 0.7599 ± 0.0001[1] M☉ |
| 半径 | 2.44[4] R☉ |
| 表面重力 (log g) | 3.0[3] |
| 亮度 | 5.311[4] L☉ |
| 温度 | 5,440 ± 100[3] K |
| 金属量 [Fe/H] | -4.1[3] dex |
| 年龄 | 13.535±0.002[1] Gyr |
| B | |
| 质量 | 0.14+0.06 −0.01[1] M☉ |
| 年龄 | 13.535±0.002[1] Gyr |
| 其他命名 | |
Gaia DR2 6702907209758894848[5]
| |
| 参考数据库 | |
| SIMBAD | 资料 |
2MASS J18082002−5104378（缩写为J1808−5104）是一个超贫金属（UMP）联星系统，位于天坛座，距离地球大约1,950 ly（600 pc）[5][6][7]，并且是单线光谱联星（SB1）。它是已知最古老的恒星之一，约有135.3亿年的历史，可能是最早的恒星之一。这颗恒星几乎完全由宇宙大爆炸释放的物质组成。一个看不见的微小伴星，一颗低质量的UMP恒星，特别不寻常。
系统
J1808−5104是一颗超贫金属（UMP）星，其对数金属丰度[Fe/H]小于−4，或太阳1/ 10,000 的级别[8]。它是一个单线光谱联星，其光谱吸收线的径向速度变化被解释为可见恒星的轨道运动。这颗伴星是看不见的，而仅是从轨道上推断出来的[1]。
J1808−5104是已知最亮的联星系统超贫金属星[8]，是太阳所在星系，银河系“薄盘”的一部分，但对于这样一颗缺乏金属的古老恒星来说是不寻常的[9]。在13.53 Gyr，这颗恒星是已知最古老的薄盘恒星，比大多数对银河系薄盘年龄的估计要早几十亿年[1]
主星
联星系统的主要组成部分，2MASS J18082002−5104378 A，是一颗比太阳冷，但更大、更亮的次巨星[3]。
伴星
看不见的伴星，2MASS J18082002−5104378 B，被认为是一颗红矮星 [5]，轨道周期 P = 34.757+0.010
−0.010日和质量为0.14 M☉[1]。它是第一颗被发现的低质量超贫金属星，也是宇宙中最古老的恒星之一，约有135.3亿年的历史[5]。它可能是最早的恒星之一，一颗几乎完全由大爆炸释放的物质形成的恒星[1][10][11][9][12][13][14][15]。
参考资料
- ^ 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].[永久失效链接]
- ^ 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].
外部链接
- [ 2MASS J18082002−5104378] 请检查
|url=值 (帮助). SIMBAD. 斯特拉斯堡天文资料中心. - [ 2MASS J18082002−5104378 B] 请检查
|url=值 (帮助). SIMBAD. 斯特拉斯堡天文资料中心. - 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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