軫宿二

**軫宿二（烏鴉座ε）**
	軫宿二的位置（紅圈）
觀測資料; 曆元 J2000
星座	烏鴉座
星官
赤經	12h 10m 07.48058s
赤緯	–22° 37′ 11.1620″
視星等（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
徑向速度 (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
詳細資料
質量	3.2 M☉
半徑	52 R☉
表面重力 (log g)	2.16
溫度	4320 K
金属量 [Fe/H]	–0.13 dex
自轉速度 (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。
參考資料庫
SIMBAD	资料

軫（zhěn）宿（xiù）二（Epsilon Corvi，ε Crv，ε Corvi）是在南天星座烏鴉座的一顆恆星，它的固有名稱Minkar /ˈmɪŋkɑːr/，源自阿拉伯語的 منقار 「minqar」，意思是「烏鴉的喙」^[10]。它的視星等為+3.0^[2]，位於距離地球318光年（97秒差距）之處^[1]。

在中國，它是軫宿的第二顆星^[11]^[12]。

軫宿二是一顆紅巨星，其恆星分類為K2III。它已經耗盡了核心的氫，在演化上易經遠離主序列。它的質量約為太陽的3倍^[6]。以干涉測量術量測得到這顆恆星的角直徑大約為4.99 毫角秒^[13]，以其估計的距離，它的真實半徑大約相當於太陽半徑的52倍^[7]。表面的有效溫度是7003432000000000000♠4320 K^[8]，使其具有K型恆星特有的橙色色調^[14]。它的質量大約是太陽的4倍，在其生命的大部分時間裏都是光譜類型為B5V的主序星^[15]。

參考資料

^ ^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） 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
^ （中文）香港太空館 - 研究資源 - 亮星中英對照表互联网档案馆的存檔，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） 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.

[12] （中文）香港太空館 - 研究資源 - 亮星中英對照表互联网档案馆的存檔，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）

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觀測資料曆元 J2000
軫宿二的位置（紅圈）
星座	烏鴉座
星官
赤經	12^h 10^m 07.48058^s^[1]
赤緯	–22° 37′ 11.1620″^[1]
視星等（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

徑向速度 (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]

詳細資料

質量	3.2^[6] M_☉
半徑	52^[7] R_☉
表面重力 (log g)	2.16^[8]
溫度	7003432000000000000♠4320^[8] K
金属量 [Fe/H]	–0.13^[8] dex
自轉速度 (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]。
參考資料庫
SIMBAD	资料