Beta Corvi

Beta Corvi or β Corvi, officially named Kraz (/ˈkræz/),[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
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]
Characteristics
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]
Astrometry
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 mas[1]
Distance146 ± 1 ly
(44.7 ± 0.4 pc)
Absolute magnitude (MV)–0.61[6]
Details
Mass3.7±0.1[3] M☉
Radius16[7] R☉
Luminosity164[8] L☉
Surface gravity (log g)2.52±0.03[3] cgs
Temperature5,100±80[3] K
Metallicity [Fe/H]–0.01[6] dex
Rotational velocity (v sin i)8[9] km/s
Age206[3] Myr
Other designations
Kraz, β Crv, Beta Corvi, Beta Crv, 9 Corvi, 9 Crv, BD−22 3401, CD−22 3401, −22 9505, CPD−22 5388, FK5 471, GC 17133, HD 109379, HIP 61359, HR 4786, SAO 180915, PPM 260512[4][10]
Database references
SIMBADdata

Nomenclature

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

In a 1951 publication, Atlas Coeli (Skalnate Pleso Atlas of the Heavens) by Czech astronomer Antonín Bečvář, it bore the name Kraz, whose origin and meaning remain unknown.[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]

Properties

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

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. Gutierrez-Moreno, Adelina; et al. (1966). "A System of photometric standards". Publications of the Department of Astronomy University of Chile. Publicaciones Universidad de Chile, Department de Astronomy. 1: 1–17. Bibcode:1966PDAUC...1....1G.
  3. 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. S2CID 119096173.
  4. 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". Determination of Radial Velocities and Their Applications, Proceedings from IAU Symposium No. 30. University of Toronto: International Astronomical Union. 30: 57. Bibcode:1967IAUS...30...57E.
  6. 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, S2CID 16258166
  7. 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
  8. 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): 1. Bibcode:1970CoAsi.239....1B.
  10. SV* ZI 946 -- Variable Star, database entry, SIMBAD. Accessed on line September 9, 2008.
  11. "Naming Stars". IAU.org. 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. 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 978-1-4614-0136-0
  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 2012-03-18, retrieved 2012-01-16
  19. 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:
  20. Kukarkin, B. V.; et al. (1981), "Nachrichtenblatt der Vereinigung der Sternfreunde e.V. (Catalogue of suspected variable stars)", Nachrichtenblatt der Vereinigung der Sternfreunde, Moscow: Academy of Sciences USSR Shternberg, Bibcode:1981NVS...C......0K
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