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.[10][4]
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]

In Chinese, 軫宿 (Zhěn Sù), meaning Chariot (asterism), refers to an asterism consisting of β Corvi, γ Corvi, ε Corvi and δ Corvi.[13] Consequently, β Corvi itself is known as 軫宿四 (Zhěn Sù sì, English: the Fourth Star of Chariot.).[14]


Beta Corvi has about 3.7 times the Sun's mass and is roughly 206 million years in age,[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.[15]

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.[16][11] 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.[17]

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. "Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30". University of Toronto: International Astronomical Union. Bibcode:1967IAUS...30...57E.  |chapter= ignored (help)
  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; 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. ^ (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.
  14. ^ (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.
  15. ^ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16 
  16. ^ 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 44.7\cdot 3.30)\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\
 & \approx 32\cdot R_{\bigodot}
  17. ^ 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