Beta Corvi

β Corvi
	Location of β Corvi (circled)
Observation data; Epoch J2000.0 Equinox J2000.0 ( ICRS)
Constellation	Corvus
Right ascension	12h 34m 23.23484s
Declination	−23° 23′ 48.3374″
Apparent magnitude (V)	2.647
Characteristics
Spectral type	G5 II
U−B color index	+0.586
B−V color index	+0.898
R−I color index	+0.44
Astrometry
Radial velocity (Rv)	−7.6 km/s
Proper motion (μ)	RA: +1.11 mas/ yr ; Dec.: −56.56 mas/ yr
Parallax (π)	22.39 ± 0.18 mas
Distance	146 ± 1 ly ; (44.7 ± 0.4 pc)
Absolute magnitude (MV)	–0.61
Details
Mass	3.7±0.1 M☉
Radius	16 R☉
Luminosity	164 L☉
Surface gravity (log g)	2.52±0.03 cgs
Temperature	5,100±80 K
Metallicity [Fe/H]	–0.01 dex
Rotational velocity (v sin i)	8 km/s
Age	206 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
Database references
SIMBAD	data

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.

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]

References

^ ^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. S2CID 18759600.
^ ^a ^b ^c ^d 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.
^ ^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. S2CID 119096173.
^ ^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.
^ 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.
^ ^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, S2CID 16258166
^ ^a ^b 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
^ ^a ^b Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics, 352: 495–507, Bibcode: 1999A&A...352..495M
^ 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.
^ SV* ZI 946 -- Variable Star, database entry, SIMBAD. Accessed on line September 9, 2008.
^ ^a ^b "Naming Stars". IAU.org. Retrieved 18 June 2018.
^ 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.
^ ^a ^b Kaler, James B., "KRAZ (Beta Corvi)", Stars, University of Illinois, retrieved 2012-12-28
^ 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
^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
^ (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.
^ (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.
^ "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
^ 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:
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 44.7\cdot 3.30)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 32\cdot R_{\bigodot }\end{aligned}}$
^ 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

[aaa474_2_653-1] ^ ^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. S2CID 18759600.

[sps1966-2] 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.

[mnras402_2_1369-3] ^ ^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. S2CID 119096173.

[bsc2-4] 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.

[rgcrv-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.

[pasj60_4_781-6] 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

[aaa431_773-7] 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

[aaa352_495-8] Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics, 352: 495–507, Bibcode: 1999A&A...352..495M

[coapa239_1-9] 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.

[sb0-10] SV* ZI 946 -- Variable Star, database entry, SIMBAD. Accessed on line September 9, 2008.

[IAU-LSN-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.

[kaler-13] Kaler, James B., "KRAZ (Beta Corvi)", Stars, University of Illinois, retrieved 2012-12-28

[falkner2011-14] 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

[WGSN-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.

[csiro-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

[lang2006-19] 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:
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 44.7\cdot 3.30)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 32\cdot R_{\bigodot }\end{aligned}}$

[csvs-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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Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS)
Location of β Corvi (circled)
Constellation	Corvus
Right ascension	12^h 34^m 23.23484^s^[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 (R_v)	−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]
Distance	146 ± 1 ly (44.7 ± 0.4 pc)
Absolute magnitude (M_V)	–0.61^[6]

Details

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	206^[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
SIMBAD	data

Nomenclature

Properties

See also

References