Beta Corvi

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β Corvi
Diagram showing star positions and boundaries of the Corvus constellation and its surroundings
Cercle rouge 100%.svg
Location of β Corvi (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Corvus
Right ascension 12h 34m 23.23484s[1]
Declination −23° 23′ 48.3374″[1]
Apparent magnitude (V) 2.647[2]
Spectral type G5 II[3]
U−B color index +0.586[2]
B−V color index +0.898[2]
R−I color index +0.44[4]
Radial velocity (Rv) −7.6[5] km/s
Proper motion (μ) RA: +1.11[1] mas/yr
Dec.: −56.56[1] mas/yr
Parallax (π) 22.39 ± 0.18[1] mas
Distance 146 ± 1 ly
(44.7 ± 0.4 pc)
Absolute magnitude (MV) –0.61[6]
Mass 3.7 ± 0.1[3] M
Radius 16[7] R
Luminosity 164[8] L
Surface gravity (log g) 2.52 ± 0.03[3] cgs
Temperature 5,100 ± 80[3] K
Metallicity [Fe/H] –0.01[6] dex
Rotational velocity (v sin i) 8[9] km/s
Age 2.06 × 108[3] years
Other designations
Kraz, β Crv, Beta Corvi, Beta Crv, 9 Corvi, 9 Crv, BD−22 3401, CD−22 3401, CD−22 9505, CPD−22 5388, FK5 471, GC 17133, HD 109379, HIP 61359, HR 4786, PPM 260512, SAO 180915.[4][10]
Database references

Beta Corvi (β Corvi, abbreviated Beta Crv, β Crv), also named Kraz,[11] is the second-brightest star in the southern constellation of Corvus with an apparent visual magnitude of 2.647.[2] Based on parallax measurements obtained during the Hipparcos mission, it is about 146 light-years (45 parsecs) distant from the Sun.


β Corvi (Latinised to Beta Corvi) is the star's Bayer designation.

It bore the traditional name of Kraz, whose origin and meaning remains unknown, though it appeared in a 1951 publication, Atlas Coeli (Skalnate Pleso Atlas of the Heavens) by Czech astronomer Antonín Bečvář.[12][13][14] In 2016, the IAU organized a Working Group on Star Names (WGSN)[15] to catalog and standardize proper names for stars. The WGSN approved the name Kraz for this star on 1 June 2018 and it is now so included in the List of IAU-approved Star Names.[11]

In Chinese, 軫宿 (Zhěn Sù), meaning Chariot (asterism), refers to an asterism consisting of Beta, Gamma, Epsilon and Delta Corvi.[16] Consequently, Beta Corvi itself is known as 軫宿四 (Zhěn Sù sì, English: the Fourth Star of Chariot).[17]


Beta Corvi has about 3.7 times the Sun's mass and is roughly 206 million years old,[3] which is old enough for a star of this mass to consume the hydrogen at its core and evolve away from the main sequence. The stellar classification is G5 II,[3] with the luminosity class of 'II' indicating this is a bright giant. The effective temperature of the star's outer envelope is about 5,100 K,[3] which produces a yellow hue common to G-type stars.[18]

The measured angular diameter of this star is 3.30 ± 0.17 mas.[7] At an estimated distance of 146 light-years (45 parsecs),[1] this yields a physical size of about 16 times the radius of the Sun.[13][19] Because of the star's mass and radius, it is emitting about 164 times the luminosity of the Sun.[8] The abundance of elements other than hydrogen or helium, what astronomers term metallicity, is similar to the proportions in the Sun.[6]

This is a variable star that ranges in apparent visual magnitude from a low of 2.66 to a high of 2.60.[20]

See also


  1. ^ a b c d e f van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Gutierrez-Moreno, Adelina; et al. (1966). "A System of photometric standards". 1. Publicaciones Universidad de Chile, Department de Astronomy: 1–17. Bibcode:1966PDAUC...1....1G. 
  3. ^ a b c d e f g h Lyubimkov, Leonid S.; et al. (February 2010). "Accurate fundamental parameters for A-, F- and G-type Supergiants in the solar neighbourhood". Monthly Notices of the Royal Astronomical Society. 402 (2): 1369–1379. arXiv:0911.1335Freely accessible. Bibcode:2010MNRAS.402.1369L. doi:10.1111/j.1365-2966.2009.15979.x. 
  4. ^ a b HR 4786, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line September 9, 2008.
  5. ^ Evans, D. S. (June 20–24, 1966). Batten, Alan Henry; Heard, John Frederick, eds. "The Revision of the General Catalogue of Radial Velocities". University of Toronto: International Astronomical Union. Bibcode:1967IAUS...30...57E. 
  6. ^ a b c Takeda, Yoichi; Sato, Bun'ei; Murata, Daisuke (August 2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, arXiv:0805.2434Freely accessible, Bibcode:2008PASJ...60..781T, doi:10.1093/pasj/60.4.781 
  7. ^ a b Richichi, A.; 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 
  8. ^ a b Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics, 352: 495–507, Bibcode:1999A&A...352..495M 
  9. ^ Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago. 239 (1). Bibcode:1970CoAsi.239....1B. 
  10. ^ SV* ZI 946 -- Variable Star, database entry, SIMBAD. Accessed on line September 9, 2008.
  11. ^ a b "Naming Stars". Retrieved 18 June 2018. 
  12. ^ Kunitzch, Paul; Smart, Tim (2006) [1986]. A Dictionary of Modern Star Names: A Short Guide to 254 Star Names and Their Derivations. Cambridge, Massachusetts: Sky Publishing Corporation. p. 62. ISBN 978-1-931559-44-7. 
  13. ^ a b Kaler, James B., "KRAZ (Beta Corvi)", Stars, University of Illinois, retrieved 2012-12-28 
  14. ^ Falkner, David E. (2011), The Mythology of the Night Sky: An Amateur Astronomer's Guide to the Ancient Greek and Roman Legends, Patrick Moore's Practical Astronomy, Springer, p. 81, ISBN 1-4614-0136-4 
  15. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016. 
  16. ^ (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.
  17. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2011-01-29 at the Wayback Machine., Hong Kong Space Museum. Accessed on line November 23, 2010.
  18. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-10, retrieved 2012-01-16 
  19. ^ Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1 . The radius (R*) is given by:
  20. ^ Kukarkin, B. V.; et al. (1981), Nachrichtenblatt der Vereinigung der Sternfreunde e.V. (Catalogue of suspected variable stars), Moscow: Academy of Sciences USSR Shternberg, Bibcode:1981NVS...C......0K 
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