毕宿四

毕宿四（金牛座γ）
γ Tauri
	; 毕宿四在毕宿星团的位置; （最右边的红点）
观测资料; 历元 J2000
星座	金牛座
星官	毕宿毕
赤经	04h 19m 47.6037s
赤纬	+15° 37′ 39.512″
视星等（V）	3.654
特性
光谱分类	G8III
U−B 色指数	+0.84
B−V 色指数	+0.99
天体测定
径向速度 (Rv)	38.7 ± 0.9 km/s
自行 (μ)	赤经：115.29 mas/yr ; 赤纬：-23.86 mas/yr
视差 (π)	21.17 ± 1.17 mas
距离	154 ± 9 ly ; (47 ± 3 pc)
绝对星等 (MV)	0.22
详细资料
质量	2.70 ± 0.13 M☉
半径	13.4 ± 0.2 R☉
表面重力 (log g)	2.58-2.61
亮度	85 L☉
温度	4,844 ± 47 K
金属量
自转速度 (v sin i)	4 km/s
年龄	4.3–5.3 × 108 年
其他命名
	Hyadum I, Prima Hyadum, 54 Tauri, HR 1346, HD 27371, HR 1346, BD+15°612, FK5 159, HIP 20205, SAO 93868, GC 5226, CCDM 04198+1538.

毕宿四，即金牛座γ（γ Tau，γ Tauri）是一颗位于金牛座的恒星，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

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，核心使用氦核聚变来提供能量^[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的高分辨率天文中心（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

在中国古代星官系统中，毕宿四属于西方白虎七宿中毕宿第四星，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

^ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 Perryman, M. A. C.; et al, The Hipparcos Catalogue, Astronomy & Astrophysics, 1997, 323: L49–L52, Bibcode:1997A&A...323L..49P
^ ^2.0 ^2.1 ^2.2 NSV 1553 - Variable Star. SIMBAD. Centre de Données astronomiques de Strasbourg. [2009-09-22]. （原始内容存档于2016-03-03）.
^ ^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.
^ ^4.0 ^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.
^ Evans, D. S. The Revision of the General Catalogue of Radial Velocities. Batten, Alan Henry; Heard, John Frederick (编). 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]. （原始内容存档于2019-06-26）.
^ ^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.
^ ^7.0 ^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.
^ 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.
^ 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.
^ ^10.0 ^10.1 Allen, R. H. Star Names: Their Lore and Meaning Reprint. New York, NY: Dover Publications Inc. 1963: 390. ISBN 0486210790.
^ 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.
^ 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.
^ 香港太空馆 - 研究资源 - 亮星中英对照表互联网档案馆的存档，存档日期2010-08-11., Hong Kong Space Museum. Accessed on line November 23, 2010.
^ 中国星座神话, written by 陈久金. Published by 台湾书房出版有限公司, 2005, ISBN 9789867332257.

[hipparcos-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 Perryman, M. A. C.; et al, The Hipparcos Catalogue, Astronomy & Astrophysics, 1997, 323: L49–L52, Bibcode:1997A&A...323L..49P

[SIMBAD-2] 2.0 ^2.1 ^2.2 NSV 1553 - Variable Star. SIMBAD. Centre de Données astronomiques de Strasbourg. [2009-09-22]. （原始内容存档于2016-03-03）.

[pasj60-3] 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.

[yerkes53-4] 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. Batten, Alan Henry; Heard, John Frederick (编). 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]. （原始内容存档于2019-06-26）.

[aaa458-6] 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.

[apj691-7] 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.

[hinckley-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] 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] 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] 香港太空馆 - 研究资源 - 亮星中英对照表互联网档案馆的存档，存档日期2010-08-11., Hong Kong Space Museum. Accessed on line November 23, 2010.

[14] 中国星座神话, written by 陈久金. Published by 台湾书房出版有限公司, 2005, ISBN 9789867332257.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

观测资料历元 J2000
毕宿四在毕宿星团的位置（最右边的红点）
星座	金牛座
星官	毕宿毕
赤经	04^h 19^m 47.6037^s^[1]
赤纬	+15° 37′ 39.512″^[1]
视星等（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

径向速度 (R_v)	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 (M_V)	0.22^[3]

详细资料

质量	2.70 ± 0.13^[6] M_☉
半径	13.4 ± 0.2^[7] R_☉
表面重力 (log g)	2.58-2.61^[7]
亮度	85^[3] L_☉
温度	4,844 ± 47^[7] K
金属量	${\begin{smallmatrix}{\frac {Fe}{H}}\ =\ 0.11\end{smallmatrix}}$ ^[8]
自转速度 (v sin i)	4^[9] km/s
年龄	4.3–5.3 × 10⁸^[3]^[6] 年

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]