Delta Corvi (δ Corvi, abbreviated Delta Crv, δ Crv), also named Algorab /ˈælɡəræb/,[9] is a third magnitude star at a distance of 86.9 light-years (26.6 parsecs) from the Sun[1] in the southern constellation of Corvus.
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Corvus |
| Right ascension | 12h 29m 51.85517s[1] |
| Declination | −16° 30′ 55.5525″[1] |
| Apparent magnitude (V) | +2.962[2] |
| Characteristics | |
| Spectral type | A0 IV(n) kB9[3] |
| U−B color index | −0.050[2] |
| B−V color index | −0.045[2] |
| Astrometry | |
| Radial velocity (Rv) | +9[4] km/s |
| Proper motion (μ) | RA: −210.49[1] mas/yr Dec.: −138.74[1] mas/yr |
| Parallax (π) | 37.55 ± 0.16 mas[1] |
| Distance | 86.9 ± 0.4 ly (26.6 ± 0.1 pc) |
| Absolute magnitude (MV) | +0.2[5] |
| Details | |
| Mass | 2.74+0.07 −0.06[6] M☉ |
| Luminosity | 69.0+9.7 −8.9[6] L☉ |
| Surface gravity (log g) | 4.06±0.05[6] cgs |
| Temperature | 10,400[6] K |
| Rotational velocity (v sin i) | 236[7] km/s |
| Age | 260+14 −24×106 or 3.2+0.1 −0.1×106[6] years |
| Other designations | |
| Database references | |
| SIMBAD | data |
Nomenclature
editδ Corvi (Latinised to Delta Corvi) is the star's Bayer designation.
It bore the traditional name Algorab derived from Arabic الغراب al-ghuraab, meaning 'the crow'. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[10] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[11] included a table of the first two batches of names approved by the WGSN; which included Algorab for this star.
In Chinese, 軫宿 (Zhěn Sù), meaning Chariot, refers to an asterism consisting of Delta Corvi, Gamma Corvi, Epsilon Corvi and Beta Corvi.[12] Consequently, Delta Corvi itself is known as 軫宿三 (Zhěn Sù sān, English: the Third Star of Chariot).[13]
Stellar properties
editDelta Corvi has more than 2.7 times the mass of the Sun, which is causing it to radiate a much higher energy output—roughly 69 times the Sun's luminosity. The effective temperature of the outer atmosphere is 10,400 K,[6] giving it the white hue of an A-type star.[14] The spectrum matches a stellar classification of A0 IV(n) kB9.[3] However, it is more luminous—65 to 70 times that of the Sun—than it would be if it were on the main sequence. Hence it is either a subgiant star around 260 million years old that has nearly exhausted the supply of hydrogen at its core and is in the process of evolving away from the main sequence of stars like the Sun, or a pre-main-sequence star around 3.2 million years old that has not completely condensed and settled on the main sequence.[6]
In 1823, Delta Corvi was found to be a wide double star by British astronomers James South and John Herschel. Since that time, the position of the two stars with respect to each other has not changed.[15] The magnitude 9.3 companion, HR 4757 B, with a classification of K2Ve, is at an angular separation of 24.2 arcseconds along a position angle of 214°.[15][16] Although the two stars share a common proper motion,[16] the significant differences in their estimated ages suggests that they may not be physically connected.[6]
A 2006 study found that Delta Corvi displayed no excess infrared emission that would otherwise suggest the presence of circumstellar matter;[17] however, warm interstellar dust was detected in a 2014 study.[18]
In culture
editUSS Algorab (AKA-8) was a United States Navy ship named after the star.
Algorab is one of the Behenian fixed stars.
References
edit- ^ 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 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
- ^ a b Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID 119476992
- ^ Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
- ^ Blondel, P. F. C.; et al. (September 2006), "Modeling of PMS Ae/Fe stars using UV spectra" (PDF), Astronomy and Astrophysics, 456 (3): 1045–1068, Bibcode:2006A&A...456.1045B, doi:10.1051/0004-6361:20040269
- ^ a b c d e f g h Montesinos, B.; et al. (March 2009), "Parameters of Herbig Ae/Be and Vega-type stars", Astronomy and Astrophysics, 495 (3): 901–917, arXiv:0811.3557, Bibcode:2009A&A...495..901M, doi:10.1051/0004-6361:200810623, S2CID 14972955
- ^ Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298
- ^ "del Crv -- Variable Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-01-30
- ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.
- ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
- ^ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 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 October 25, 2008, 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
- ^ a b Garfinkle, Robert A. (1997), Star-Hopping: Your Visa to Viewing the Universe, Cambridge University Press, p. 109, ISBN 0-521-59889-3
- ^ a b Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976
- ^ Su, K. Y. L.; et al. (December 2006), "Debris Disk Evolution around A Stars", The Astrophysical Journal, 653 (1): 675–689, arXiv:astro-ph/0608563, Bibcode:2006ApJ...653..675S, doi:10.1086/508649, S2CID 14116473
- ^ Ertel, S.; Absil, O.; Defrère, D.; Le Bouquin, J.-B.; Augereau, J.-C.; Marion, L.; Blind, N.; Bonsor, A.; Bryden, G.; Lebreton, J.; Milli, J. (2014). "A near-infrared interferometric survey of debris-disk stars. IV. An unbiased sample of 92 southern stars observed in H band with VLTI/PIONIER". Astronomy & Astrophysics. 570: 20. arXiv:1409.6143. Bibcode:2014A&A...570A.128E. doi:10.1051/0004-6361/201424438. S2CID 9594917. A128.