Astronomy:Beta Corvi
Observation data 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[1] mas |
Distance | 146 ± 1 ly (44.7 ± 0.4 pc) |
Absolute magnitude (MV) | –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 | |
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]
See also
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 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.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 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. doi:10.1111/j.1365-2966.2009.15979.x. Bibcode: 2010MNRAS.402.1369L.
- ↑ 4.0 4.1 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.
- ↑ 6.0 6.1 6.2 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, doi:10.1093/pasj/60.4.781, Bibcode: 2008PASJ...60..781T
- ↑ 7.0 7.1 Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics 431 (2): 773–777, doi:10.1051/0004-6361:20042039, Bibcode: 2005A&A...431..773R
- ↑ 8.0 8.1 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.
- ↑ 11.0 11.1 "Naming Stars". IAU.org. https://www.iau.org/public/themes/naming_stars/.
- ↑ Kunitzch, Paul; Smart, Tim (2006). 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.
- ↑ 13.0 13.1 Kaler, James B., "KRAZ (Beta Corvi)", Stars (University of Illinois), http://stars.astro.illinois.edu/sow/kraz.html, 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, https://books.google.com/books?id=tyj8UUE968wC&pg=PA81
- ↑ "IAU Working Group on Star Names (WGSN)". https://www.iau.org/science/scientific_bodies/working_groups/280/.
- ↑ (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 , 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, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16
- ↑ Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41. The radius (R*) is given by:
- [math]\displaystyle{ \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} \end{align} }[/math]
- ↑ 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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