Epsilon Corvi

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Epsilon Corvi
Diagram showing star positions and boundaries of the Corvus constellation and its surroundings
Cercle rouge 100%.svg

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[1] mas
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 4,320[8] K
Metallicity [Fe/H] –0.13[8] dex
Rotational velocity (v sin i) 1.0[6] km/s
Other designations
2 Crv, FK5 453, HD 105707, HIP 59316, HR 4630, SAO 180531.[9]

Epsilon Corvi (ε Crv, ε Corvi) is a star in the southern constellation of Corvus. It has the traditional name Minkar, from Arabic المنخر al-mánxar meaning "the nostril 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]

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 giant star 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 4,320 K,[8] giving it an orange hue that is characteristic of a K-type star.[14]

References[edit]

  1. ^ a b c d 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 
  2. ^ a b c d 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 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 (35), Astronomisches Rechen-Institut Heidelberg, 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 
  6. ^ a b c 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 
  7. ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library 1 (3 ed.), Birkhäuser, ISBN 3-540-29692-1 . The radius (R*) is given by:
    \begin{align} 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{align}
  8. ^ a b c d 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 2012-01-24-23 
  10. ^ Constellations of Words - Corvi (Minkar)
  11. ^ (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. ^ (Chinese) 香港太空館 - 研究資源 - 亮星中英對照表, Hong Kong Space Museum. Accessed on line November 23, 2010.
  13. ^ Richichi; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics 431: 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, retrieved 2012-01-16