HD 74772

HD 74772
Observation data
Epoch J2000      Equinox J2000
Constellation Vela
Right ascension 08h 44m 23.94539s[1]
Declination −42° 38′ 57.3933″[1]
Apparent magnitude (V) 4.05[2]
Characteristics
Spectral type G6 III[3]
B−V color index 0.874±0.002[2]
Astrometry
Radial velocity (Rv)−2.0±0.3[4] km/s
Proper motion (μ) RA: −22.641[1] mas/yr
Dec.: +19.137[1] mas/yr
Parallax (π)15.7791 ± 0.3148[1] mas
Distance207 ± 4 ly
(63 ± 1 pc)
Absolute magnitude (MV)−0.18[2]
Details
Mass3.2[5] M☉
Radius12[6] R☉
Luminosity128.02[2] L☉
Surface gravity (log g)2.50[7] cgs
Temperature5,210[7] K
Metallicity [Fe/H]−0.03[7] dex
Rotational velocity (v sin i)5.8[8] km/s
Other designations
d Vel, CD−42° 4569, GJ 9276, HD 74772, HIP 42884, HR 3477, SAO 220371, WDS J08444-4239A[9]
Database references
SIMBADdata

HD 74772 (d Velorum) is a single[10] star in the southern constellation of Vela. It is positioned near the Vela SNR, which gives it an intense X-ray background.[11] The star is of apparent visual magnitude 4.05,[2] and hence is visible to the naked eye. Based upon an annual parallax shift of 15.8 mas,[1] it is located 207 light years from the Sun. It is moving closer to the Earth with a heliocentric radial velocity of −2 km/s.[4]

This is an evolved G-type giant star with a stellar classification of G6 III.[3] The interferometry-measured angular diameter of this star is 1.73±0.12 mas,[12] which, at its estimated distance, equates to a physical radius of about 12 times the radius of the Sun.[6] It has 3.2[5] times the mass of the Sun and is radiating 128[2] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,210 K.[7]

References

  1. 1 2 3 4 5 6 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
  2. 1 2 3 4 5 6 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  3. 1 2 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
  4. 1 2 de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  5. 1 2 Gondoin, P. (December 1999), "Evolution of X-ray activity and rotation on G-K giants", Astronomy and Astrophysics, 352: 217–227, Bibcode:1999A&A...352..217G.
  6. 1 2 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1 . The radius (R*) is given by:
  7. 1 2 3 4 Jones, K. L.; et al. (June 1992), "Spectroscopic investigation of cool giants and the authenticity of their reported microwave emission", Monthly Notices of the Royal Astronomical Society, 256 (3): 535–544, Bibcode:1992MNRAS.256..535J, doi:10.1093/mnras/256.3.535.
  8. ↑ de Medeiros, J. R.; Mayor, M. (October 1995), "On the link between rotation and coronal activity in evolved stars", Astronomy and Astrophysics, 302: 745, Bibcode:1995A&A...302..745D.
  9. ↑ "HD 74772". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-08-07.
  10. ↑ Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  11. ↑ Maggio, A.; et al. (1993), "Soft X-ray Emission and Spectra of Evolved Stars from ROSAT Pointed Observations", in Linsky, Jeffrey L.; Serio, Salvatore, Physics of Solar and Stellar Coronae: G. S. Vaiana Memorial Symposium, held 22-26 June, 1992, in Palermo, Italy, Astrophysics and Space Science Library, 183, P. O. Box 17, 3300 AA Dordrecht, The Netherlands: Kluwer Academoc Publishers, p. 365, Bibcode:1993ASSL..183..365M, doi:10.1007/978-94-011-1964-1_47.
  12. ↑ Richichi, A.; et al. (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.
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