轸宿二

**轸宿二（乌鸦座ε）**
	轸宿二的位置（红圈）
观测资料; 历元 J2000
星座	乌鸦座
星官
赤经	12h 10m 07.48058s
赤纬	–22° 37′ 11.1620″
视星等（V）	+3.024
特性
光谱分类	K2 III
U−B 色指数	+1.458
B−V 色指数	+1.318
天体测定
径向速度 (Rv)	+4.9 km/s
自行 (μ)	赤经：–71.74 mas/yr ; 赤纬：+10.25 mas/yr
视差 (π)	10.26 ± 0.16 mas
距离	318 ± 5 ly ; (97 ± 2 pc)
绝对星等 (MV)	−1.82+0.15; −0.14
详细资料
质量	3.2 M☉
半径	52 R☉
表面重力 (log g)	2.16
温度	4320 K
金属量 [Fe/H]	–0.13 dex
自转速度 (v sin i)	1.0 km/s
其他命名
	2 Crv、BD−21° 3487、 FK5 453、HD 105707、HIP 59316、HR 4630、SAO 180531。
参考数据库
SIMBAD	资料

轸（zhěn）宿（xiù）二（Epsilon Corvi，ε Crv，ε Corvi）是在南天星座乌鸦座的一颗恒星，它的固有名称Minkar /ˈmɪŋkɑːr/，源自阿拉伯语的 منقار “minqar”，意思是“乌鸦的喙”^[10]。它的视星等为+3.0^[2]，位于距离地球318光年（97秒差距）之处^[1]。

在中国，它是轸宿的第二颗星^[11]^[12]。

轸宿二是一颗红巨星，其恒星分类为K2III。它已经耗尽了核心的氢，在演化上易经远离主序列。它的质量约为太阳的3倍^[6]。以干涉测量术量测得到这颗恒星的角直径大约为4.99 毫角秒^[13]，以其估计的距离，它的真实半径大约相当于太阳半径的52倍^[7]。表面的有效温度是7003432000000000000♠4320 K^[8]，使其具有K型恒星特有的橙色色调^[14]。它的质量大约是太阳的4倍，在其生命的大部分时间里都是光谱类型为B5V的主序星^[15]。

参考资料

^ ^1.0 ^1.1 ^1.2 ^1.3 van Leeuwen, F., Validation of the new Hipparcos reduction, Astronomy and Astrophysics, November 2007, 474 (2): 653–664, Bibcode:2007A&A...474..653V, S2CID 18759600, arXiv:0708.1752  , doi:10.1051/0004-6361:20078357
^ ^2.0 ^2.1 ^2.2 ^2.3 Celis S., L., Photoelectric photometry of late-type variable stars, Astronomy and Astrophysics Supplement Series, October 1975, 22: 9–17, Bibcode:1975A&AS...22....9C
^ Houk, Nancy, Michigan catalogue of two-dimensional spectral types for the HD stars 4, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, 1979, Bibcode:1988mcts.book.....H
^ Wielen, R.; et al, Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions, Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg (Astronomisches Rechen-Institut Heidelberg), 1999, 35 (35): 1, Bibcode:1999VeARI..35....1W
^ Carney, Bruce W.; et al, Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars, The Astronomical Journal, March 2008, 135 (3): 892–906, Bibcode:2008AJ....135..892C, S2CID 2756572, arXiv:0711.4984  , doi:10.1088/0004-6256/135/3/892
^ ^6.0 ^6.1 ^6.2 Melo, C. H. F.; et al, On the nature of lithium-rich giant stars. Constraints from beryllium abundances, Astronomy and Astrophysics, August 2005, 439 (1): 227–235, Bibcode:2005A&A...439..227M, S2CID 10580797, arXiv:astro-ph/0504133  , doi:10.1051/0004-6361:20041805
^ ^7.0 ^7.1 Lang, Kenneth R., Astrophysical formulae, Astronomy and astrophysics library 1 3rd, Birkhäuser, 2006 [2024-04-02], ISBN 3-540-29692-1, （原始内容存档于2023-07-28） . The radius (R_*) is given by:
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 97\cdot 4.99)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 104\cdot R_{\bigodot }\end{aligned}}$
^ ^8.0 ^8.1 ^8.2 ^8.3 McWilliam, Andrew, High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances, Astrophysical Journal Supplement Series, December 1990, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527 
^ MINKAR -- Variable Star, SIMBAD (Centre de Données astronomiques de Strasbourg), [2012-01-23], （原始内容存档于2024-04-11）
^ Al-Sufi, Book Of Fixed Stars, Constellation: The Crow. [2024-04-02]. （原始内容存档于2020-10-03）.
^ （中文） 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 978-986-7332-25-7.
^ （中文）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January 30, 2011，., Hong Kong Space Museum. Accessed on line November 23, 2010.
^ Richichi, A.; Percheron, I.; Khristoforova, M., CHARM2: An updated Catalog of High Angular Resolution Measurements, Astronomy and Astrophysics, February 2005, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039 
^ The Colour of Stars, Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004 [2012-01-16], （原始内容存档于2012-03-18）
^ Kaler, James B. (Jim), Minkar, Stars (University of Illinois), [12 July 2015], （原始内容存档于2021-04-15）

[aaa474_2_653-1] 1.0 ^1.1 ^1.2 ^1.3 van Leeuwen, F., Validation of the new Hipparcos reduction, Astronomy and Astrophysics, November 2007, 474 (2): 653–664, Bibcode:2007A&A...474..653V, S2CID 18759600, arXiv:0708.1752  , doi:10.1051/0004-6361:20078357

[aaass22_9-2] 2.0 ^2.1 ^2.2 ^2.3 Celis S., L., Photoelectric photometry of late-type variable stars, Astronomy and Astrophysics Supplement Series, October 1975, 22: 9–17, Bibcode:1975A&AS...22....9C

[houk1979-3] Houk, Nancy, Michigan catalogue of two-dimensional spectral types for the HD stars 4, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, 1979, Bibcode:1988mcts.book.....H

[scfs-4] Wielen, R.; et al, Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions, Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg (Astronomisches Rechen-Institut Heidelberg), 1999, 35 (35): 1, Bibcode:1999VeARI..35....1W

[aj135_3_892-5] Carney, Bruce W.; et al, Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars, The Astronomical Journal, March 2008, 135 (3): 892–906, Bibcode:2008AJ....135..892C, S2CID 2756572, arXiv:0711.4984  , doi:10.1088/0004-6256/135/3/892

[aaa439_1_227-6] 6.0 ^6.1 ^6.2 Melo, C. H. F.; et al, On the nature of lithium-rich giant stars. Constraints from beryllium abundances, Astronomy and Astrophysics, August 2005, 439 (1): 227–235, Bibcode:2005A&A...439..227M, S2CID 10580797, arXiv:astro-ph/0504133  , doi:10.1051/0004-6361:20041805

[lang2006-7] 7.0 ^7.1 Lang, Kenneth R., Astrophysical formulae, Astronomy and astrophysics library 1 3rd, Birkhäuser, 2006 [2024-04-02], ISBN 3-540-29692-1, （原始内容存档于2023-07-28） . The radius (R_*) is given by:
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 97\cdot 4.99)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 104\cdot R_{\bigodot }\end{aligned}}$

[ajss74_1075-8] 8.0 ^8.1 ^8.2 ^8.3 McWilliam, Andrew, High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances, Astrophysical Journal Supplement Series, December 1990, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527 

[SIMBAD-9] MINKAR -- Variable Star, SIMBAD (Centre de Données astronomiques de Strasbourg), [2012-01-23], （原始内容存档于2024-04-11）

[10] Al-Sufi, Book Of Fixed Stars, Constellation: The Crow. [2024-04-02]. （原始内容存档于2020-10-03）.

[11] （中文） 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 978-986-7332-25-7.

[12] （中文）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January 30, 2011，., Hong Kong Space Museum. Accessed on line November 23, 2010.

[aaa431_773-13] Richichi, A.; Percheron, I.; Khristoforova, M., CHARM2: An updated Catalog of High Angular Resolution Measurements, Astronomy and Astrophysics, February 2005, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039 

[csiro-14] The Colour of Stars, Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004 [2012-01-16], （原始内容存档于2012-03-18）

[kalereps-15] Kaler, James B. (Jim), Minkar, Stars (University of Illinois), [12 July 2015], （原始内容存档于2021-04-15）

[10]

[2]

[1]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[11]

[12]

[13]

[14]

[15]

观测资料历元 J2000
轸宿二的位置（红圈）
星座	乌鸦座
星官
赤经	12^h 10^m 07.48058^s^[1]
赤纬	–22° 37′ 11.1620″^[1]
视星等（V）	+3.024^[2]
特性
光谱分类	K2 III^[3]
U−B 色指数	+1.458^[2]
B−V 色指数	+1.318^[2]
天体测定

径向速度 (R_v)	+4.9^[4] km/s
自行 (μ)	赤经：–71.74 mas/yr 赤纬：+10.25 mas/yr
视差 (π)	10.26 ± 0.16^[1] mas
距离	318 ± 5 ly (97 ± 2 pc)
绝对星等 (M_V)	2999818000000000000♠−1.82+0.15 −0.14^[5]

详细资料

质量	3.2^[6] M_☉
半径	52^[7] R_☉
表面重力 (log g)	2.16^[8]
温度	7003432000000000000♠4320^[8] K
金属量 [Fe/H]	–0.13^[8] dex
自转速度 (v sin i)	1.0^[6] km/s

其他命名
2 Crv、BD−21° 3487、 FK5 453、HD 105707、HIP 59316、HR 4630、SAO 180531^[9]。
参考数据库
SIMBAD	资料