Beta Corvi

From Wikipedia, the free encyclopedia
Jump to: navigation, search
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 (Beta Crv, β Corvi, β Crv) is the second brightest star in the southern constellation of Corvus. It has the traditional name Kraz. The origin and meaning of this name remains uncertain.[11][12]


The Proper Name Kraz for Beta Corvi appeared in a 1951 publication, Atlas Coeli (Skalnate Pleso Atlas of the Heavens) by Czech astronomer Antonín Bečvář. Professor Paul Kunitzch has been unable to find any clues as to the origin of the name. [13]

In Chinese, 軫宿 (Zhěn Sù), meaning Chariot (asterism), refers to an asterism consisting of β Corvi, γ Corvi, ε Corvi and δ Corvi.[14] Consequently, β Corvi itself is known as 軫宿四 (Zhěn Sù sì, English: the Fourth Star of Chariot.).[15]


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.[16]

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.[11][17] 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.[18]

See also[edit]


  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:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  2. ^ a b c Gutierrez-Moreno, Adelina et al. (1966). "A System of photometric standards" 1. Publicaciones Universidad de Chile, Department de Astronomy. pp. 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:0911.1335. 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:0805.2434, 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 Kaler, James B., "KRAZ (Beta Corvi)", Stars (University of Illinois), retrieved 2012-12-28 
  12. ^ 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 
  13. ^ 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. 
  14. ^ (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.
  15. ^ (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.
  16. ^ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16 
  17. ^ 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:
    \begin{align} 2\cdot R_*
 & = \frac{(10^{-3}\cdot 44.7\cdot 3.30)\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\
 & \approx 32\cdot R_{\bigodot}
  18. ^ 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