Beta Corvi

Beta Corvi or β Corvi, officially named Kraz (/ˈkræz/),^[9] 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.^[1]

β Corvi

Location of β Corvi (circled in red)
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)	−7.34±0.08 [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]
Distance	146 ± 1 ly (44.7 ± 0.4 pc)
Absolute magnitude (MV)	−0.651±0.033[6]
Details
Mass	3.32±0.06[5] M☉
Radius	15.84±0.72[7] R☉
Luminosity	175+13 −12[6] L☉
Surface gravity (log g)	2.86±0.06[7] cgs
Temperature	5325±28[6] K
Metallicity [Fe/H]	0.14±0.02[6] dex
Rotational velocity (v sin i)	2.58±0.55[5] km/s
Age	280±10[5] 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][8]
Database references
SIMBAD	data

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.^[10][11][12]

In 2016, the IAU organized a Working Group on Star Names (WGSN)^[13] 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.^[9]

In Chinese, 軫宿 (Zhěn Sù), meaning Chariot (asterism), refers to an asterism consisting of Beta, Gamma, Epsilon and Delta Corvi.^[14] Consequently, Beta Corvi itself is known as 軫宿四 (Zhěn Sù sì, English: the Fourth Star of Chariot).^[15]

Properties

Beta Corvi has about 3.3 times the Sun's mass and is roughly 300 million years old,^[5] 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 5,325 K,^[6] which produces a yellow hue common to G-type stars.^[16]

Currently, Beta Corvi has expanded to 15.8^[7] times the Sun's size and is emitting about 175 times the luminosity of the Sun. The abundance of elements other than hydrogen or helium, what astronomers term metallicity, is 1.38 times that of the Sun.^[6][a]

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

• List of stars in Corvus
• Beta Leporis, another bright giant star with similar size and spectral type

Notes

1. The abundance is estimated by taking [Fe/H] to the power of ten:
             10^[Fe/H] = 10^+0.14 = 1.38

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. 1. Publicaciones Universidad de Chile, Department de Astronomy: 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. Jofré, E.; Petrucci, R.; Saffe, C.; Saker, L.; Artur de la Villarmois, E.; Chavero, C.; Gómez, M.; Mauas, P. J. D. (2015-02-01). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy and Astrophysics. 574: A50. arXiv:1410.6422. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. ISSN 0004-6361. Beta Corvi's database entry at VizieR.
6. Rosas-Portilla, F.; Schröder, K.-P.; Jack, D. (2022-04-26). "On the physical nature of the Wilson-Bappu effect: revising the gravity and temperature dependence". Monthly Notices of the Royal Astronomical Society. 513 (1): 906–924. arXiv:2203.16593. Bibcode:2022csss.confE.216R. doi:10.1093/mnras/stac929. ISSN 0035-8711.
7. Gomes da Silva, J.; Santos, N. C.; Adibekyan, V.; Sousa, S. G.; Campante, T. L.; Figueira, P.; Bossini, D.; Delgado-Mena, E.; Monteiro, M. J. P. F. G.; de Laverny, P.; Recio-Blanco, A.; Lovis, C. (2021-02-01). "Stellar chromospheric activity of 1674 FGK stars from the AMBRE-HARPS sample. I. A catalogue of homogeneous chromospheric activity". Astronomy and Astrophysics. 646: A77. arXiv:2012.10199. Bibcode:2021A&A...646A..77G. doi:10.1051/0004-6361/202039765. ISSN 0004-6361. Beta Corvi's database entry at VizieR.
8. SV* ZI 946 -- Variable Star, database entry, SIMBAD. Accessed on line September 9, 2008.
9. "Naming Stars". IAU.org. Retrieved 18 June 2018.
10. 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.
11. 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 978-1-4614-0136-0
13. "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
14. (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.
15. (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.
16. "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
17. 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