Delta Corvi

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Delta Corvi
Diagram showing star positions and boundaries of the Corvus constellation and its surroundings
Cercle rouge 100%.svg

Location of δ Corvi (circled)
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[1] mas
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
[6] years
Other designations
7 Crv, BD−15 3482, FK5 465, HD 108767, HIP 60965, HR 4757, SAO 157323.[8]

Delta Corvi (δ Crv, δ Corvi) is a star in the southern constellation of Corvus. It has the traditional name Algorab (from Arabic الغراب al-ghuraab, meaning "the crow"). This is a third magnitude star at a distance of 86.9 light-years (26.6 parsecs) from Earth. In 1823, it 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.[9]

This star 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.[10] The spectrum matches a stellar classification of A0 IV(n) kB9.[3] Although it is only around 260 million years old,[6] the luminosity class of 'IV' indicates this is a subgiant star 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.

Algorab displays no excess infrared emission that would otherwise suggest the presence of circumstellar matter.[11] It has a magnitude 9.3 companion, HR 4757 B, with a classification of K2Ve at an angular separation of 24.2 arcseconds along a position angle of 214°.[9][12] Although the two stars share a common proper motion,[12] the significant differences in their estimated ages suggests that they may not be physically connected.[6]

In Chinese, 軫宿 (Zhěn Sù), meaning Chariot (asterism), refers to an asterism consisting of δ Corvi, γ Corvi, ε Corvi and β Corvi.[13] Consequently, δ Corvi itself is known as 軫宿三 (Zhěn Sù sān, English: the Third Star of Chariot.).[14]

USS Algorab (AKA-8) is a United States navy ship.

References[edit]

  1. ^ a b c d e 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 
  2. ^ a b c Gutierrez-Moreno, Adelina et al. (1966), A System of photometric standards 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17, Bibcode:1966PDAUC...1....1G 
  3. ^ 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 
  4. ^ Wilson, Ralph Elmer (1953). General Catalogue of Stellar Radial Velocities. Washington: Carnegie Institution of Washington. Bibcode:1953QB901.W495..... 
  5. ^ Blondel, P. F. C. et al. (September 2006), "Modeling of PMS Ae/Fe stars using UV spectra", Astronomy and Astrophysics 456 (3): 1045–1068, Bibcode:2006A&A...456.1045B, doi:10.1051/0004-6361:20040269 
  6. ^ 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 
  7. ^ 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 
  8. ^ "del Crv -- Variable Star", SIMBAD (Centre de Données astronomiques de Strasbourg), retrieved 2012-01-30 
  9. ^ a b Garfinkle, Robert A. (1997), Star-Hopping: Your Visa to Viewing the Universe, Cambridge University Press, p. 109, ISBN 0-521-59889-3 
  10. ^ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16 
  11. ^ 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 
  12. ^ 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 
  13. ^ (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.
  14. ^ (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.