毕宿四

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毕宿四(金牛座γ)
γ Tauri
HyadesStarMap.jpg
毕宿四在毕宿星团的位置
(最右边的红点)
觀測資料
曆元 J2000
星座 金牛座
星官 毕宿
赤經 04h 19m 47.6037s[1]
赤緯 +15° 37′ 39.512″[1]
視星等(V) 3.654[2]
特性
光谱分类G8III[3]
U−B 色指数+0.84[4]
B−V 色指数+0.99[4]
天体测定
徑向速度 (Rv)38.7 ± 0.9[5] km/s
自行 (μ) 赤经:115.29[1] mas/yr
赤纬:-23.86[1] mas/yr
视差 (π)21.17 ± 1.17[1] mas
距离154 ± 9 ly
(47 ± 3 pc)
绝对星等 (MV)0.22[3]
詳細資料
質量2.70 ± 0.13[6] M
半徑13.4 ± 0.2[7] R
表面重力 (log g)2.58-2.61[7]
亮度85[3] L
溫度4,844 ± 47[7] K
金屬量[8]
自轉速度 (v sin i)4[9] km/s
年齡4.3–5.3 × 108[3][6]
其他命名
Hyadum I, Prima Hyadum,[10] 54 Tauri, HR 1346, HD 27371, HR 1346, BD+15°612, FK5 159, HIP 20205, SAO 93868, GC 5226, CCDM 04198+1538.[2]

毕宿四,即金牛座γ(γ Tau,γ Tauri)是一颗位于金牛座恒星,它是离太阳系最近的疏散星团——毕宿星团的成员之一。它和毕宿星团的其他亮星以及附近的毕宿五一起组成金牛座的头部。

特征[编辑]

毕宿四是一颗G8型或K0型巨星[2][3]视星等为+3.65。它距离毕宿星团的中心仅有2.5秒差距。这颗恒星已经度过主序星阶段,现在膨胀成为红巨星,核心使用核聚变来提供能量[11]。它的年龄估计介于4.3亿年[3]至5.3亿年[6]之间。相对的,毕宿星团的年龄约为6.25亿年,存在0.5亿年的误差[12]

天文学家对毕宿四的视差测量为21.17±1.17角分,据此计算出它距离地球约154光年(47秒差距)。毕宿四的角直径已经为威尔逊山天文台高分辨率天文中心(CHARA array)所测量,它的精度为+/- 2%。通过对毕宿四周边昏暗效应的校正,计算出恒星的半径约是太阳半径的13.4倍[7]。毕宿四的光度是太阳光度的85倍[3],质量是太阳质量的2.7倍[6],表面温度约为4970K

命名[编辑]

中国古代星官系统中,毕宿四属于西方白虎七宿毕宿第四星,这也是毕宿四名字的来由[13][14]

它的西方传统名字为Hyadum I[10],在拉丁语中是“毕宿星团第一星”的意思。

毕宿四的拜耳命名法为金牛座γ,佛氏命名为金牛座54,HD星表中编号第27371,依巴谷星表编号第20205。

参考资料[编辑]

  1. ^ 1.0 1.1 1.2 1.3 1.4 Perryman, M. A. C.; 等, The Hipparcos Catalogue, Astronomy & Astrophysics, 1997, 323: L49–L52, Bibcode:1997A&A...323L..49P 
  2. ^ 2.0 2.1 2.2 NSV 1553 - Variable Star. SIMBAD. Centre de Données astronomiques de Strasbourg. [2009-09-22]. 
  3. ^ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Takeda, Yoichi; Sato, Bun'ei; Murata, Daisuke. Stellar Parameters and Elemental Abundances of Late-G Giants. Publications of the Astronomical Society of Japan. August 2008, 60 (4): 781–802. Bibcode:2008PASJ...60..781T. 
  4. ^ 4.0 4.1 Johnson, H. L.; Morgan, W. W. Fundamental stellar photometry for standards of spectral type on the revised system of the Yerkes spectral atlas. Astrophysical Journal. 1953, 117: 313–352. Bibcode:1953ApJ...117..313J. doi:10.1086/145697. 
  5. ^ Evans, D. S. The Revision of the General Catalogue of Radial Velocities. (编) Batten, Alan Henry; Heard, John Frederick. Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. University of Toronto: International Astronomical Union. June 20–24, 1966 [2009-09-10]. 
  6. ^ 6.0 6.1 6.2 6.3 da Silva, L.; et al. Basic physical parameters of a selected sample of evolved stars. Astronomy and Astrophysics. November 2006, 458 (2): 609–623. Bibcode:2006A&A...458..609D. arXiv:astro-ph/0608160. doi:10.1051/0004-6361:20065105. 
  7. ^ 7.0 7.1 7.2 7.3 Boyajian, Tabetha S.; et al. Angular Diameters of the Hyades Giants Measured with the CHARA Array. The Astrophysical Journal. February 2009, 691 (2): 1243–1247. Bibcode:2009ApJ...691.1243B. doi:10.1088/0004-637X/691/2/1243. 
  8. ^ Soubiran, C.; Bienaymé, O.; Mishenina, T. V.; Kovtyukh, V. V. Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants. Astronomy and Astrophysics. March 2008, 480 (1): 91–101. Bibcode:2008A&A...480...91S. doi:10.1051/0004-6361:20078788. 
  9. ^ Bernacca, P. L.; Perinotto, M. A catalogue of stellar rotational velocities. Contributi Osservatorio Astronomico di Padova in Asiago. 1970, 239 (1). Bibcode:1970CoAsi.239....1B. 
  10. ^ 10.0 10.1 Allen, R. H. Star Names: Their Lore and Meaning Reprint. New York, NY: Dover Publications Inc. 1963: 390. ISBN 0486210790. 
  11. ^ de Bruijne, J. H. J.; Hoogerwerf, R.; de Zeeuw, P. T. A Hipparcos study of the Hyades open cluster. Improved colour-absolute magnitude and Hertzsprung-Russell diagrams. Astronomy and Astrophysics. February 2001, 367 (1): 111–147. Bibcode:2001A&A...367..111D. arXiv:astro-ph/0011565. doi:10.1051/0004-6361:20000410. 
  12. ^ da Silva, L.; et al. Basic physical parameters of a selected sample of evolved stars. Astronomy and Astrophysics. November 2006, 458 (2): 609–623. Bibcode:2006A&A...458..609D. arXiv:astro-ph/0608160. doi:10.1051/0004-6361:20065105. 
  13. ^ 香港太空館 - 研究資源 - 亮星中英對照表 互联网档案馆存檔,存档日期2010-08-11., Hong Kong Space Museum. Accessed on line November 23, 2010.
  14. ^ 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 9789867332257.