Epsilon Corvi

Epsilon Corvi (ε Crv, ε Corvi) is a star in the southern constellation of Corvus. It has the traditional name Minkar /ˈmɪŋkɑːr/, from Arabic منقار minqar meaning "beak [of the crow]"^[10] The apparent visual magnitude is +3.0^[2] and it is located at a distance of 318 light-years (97 parsecs) from Earth.^[1]

ε Corvi

Location of ε Corvi (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Corvus
Right ascension	12h 10m 07.48058s[1]
Declination	–22° 37′ 11.1620″[1]
Apparent magnitude (V)	+3.024[2]
Characteristics
Spectral type	K2 III[3]
U−B color index	+1.458[2]
B−V color index	+1.318[2]
Astrometry
Radial velocity (Rv)	+4.9[4] km/s
Proper motion (μ)	RA: –71.74 mas/yr Dec.: +10.25 mas/yr
Parallax (π)	10.26 ± 0.16 mas[1]
Distance	318 ± 5 ly (97 ± 2 pc)
Absolute magnitude (MV)	−1.82+0.15 −0.14[5]
Details
Mass	3.2[6] M☉
Radius	52[7] R☉
Surface gravity (log g)	2.16[8] cgs
Temperature	4320[8] K
Metallicity [Fe/H]	–0.13[8] dex
Rotational velocity (v sin i)	1.0[6] km/s
Other designations
2 Crv, BD−21° 3487, FK5 453, HD 105707, HIP 59316, HR 4630, SAO 180531.[9]
Database references
SIMBAD	data

In Chinese, 軫宿 (Zhěn Sù), meaning Chariot (asterism), refers to an asterism consisting of ε Corvi, γ Corvi, δ Corvi and β Corvi.^[11] Consequently, ε Corvi itself is known as 軫宿二 (Zhěn Sù èr, English: the Second Star of Chariot.).^[12]

Epsilon Corvi is a red giant with a stellar classification of K2 III, having consumed the hydrogen at its core and evolved away from the main sequence. It has about three times the Sun's mass.^[6] The interferometry-measured angular diameter of this star is about 4.99 mas,^[13] which, at its estimated distance, equates to a physical radius of about 52 times the radius of the Sun.^[7] The effective temperature of the outer envelope is 4320 K,^[8] giving it an orange hue that is characteristic of a K-type star.^[14] Around 4 times as massive as the Sun, it spent much of its life as a main sequence star of spectral type B5V.^[15]

References

1. van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600
2. Celis S., L. (October 1975), "Photoelectric photometry of late-type variable stars", Astronomy and Astrophysics Supplement Series, 22: 9–17, Bibcode:1975A&AS...22....9C
3. Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H
4. Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W
5. Carney, Bruce W.; et al. (March 2008), "Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars", The Astronomical Journal, 135 (3): 892–906, arXiv:0711.4984, Bibcode:2008AJ....135..892C, doi:10.1088/0004-6256/135/3/892, S2CID 2756572
6. Melo, C. H. F.; et al. (August 2005), "On the nature of lithium-rich giant stars. Constraints from beryllium abundances", Astronomy and Astrophysics, 439 (1): 227–235, arXiv:astro-ph/0504133, Bibcode:2005A&A...439..227M, doi:10.1051/0004-6361:20041805, S2CID 10580797
7. Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R_*) is given by:

   ${\displaystyle {\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 97\cdot 4.99)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 104\cdot R_{\bigodot }\end{aligned}}}$

8. McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527
9. "MINKAR -- Variable Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-01-23
10. Al-Sufi, Book Of Fixed Stars, Constellation: The Crow
11. (in Chinese) 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. (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived January 30, 2011, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
13. Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039
14. "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-18, retrieved 2012-01-16
15. Kaler, James B. (Jim), "Minkar", Stars, University of Illinois, retrieved 12 July 2015