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HD 79940

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HD 79940
Location of HD 79940 (circled in red)
Observation data
Epoch J2000.0      Equinox ICRS
Constellation Vela[1]
Right ascension 09h 15m 45.07943s[2]
Declination −37° 24′ 47.3124″[2]
Apparent magnitude (V) 4.63[3]
Characteristics
Spectral type F3/5V[4] or F5III[5][6]
B−V color index 0.473±0.002[3]
Astrometry
Radial velocity (Rv)+5.8±2.8[3] km/s
Proper motion (μ) RA: +14.128[2] mas/yr
Dec.: −8.111[2] mas/yr
Parallax (π)20.5985±0.1895 mas[2]
Distance158 ± 1 ly
(48.5 ± 0.4 pc)
Absolute magnitude (MV)1.12[3]
Details
Mass1.36[7] M☉
Radius4.35+0.11
−0.19[2] R☉
Luminosity28.427±0.305[2] L☉
Surface gravity (log g)3.26±0.14[7] cgs
Temperature6,388+143
−76[2] K
Metallicity [Fe/H]0.20±0.15[3] dex
Rotational velocity (v sin i)117.2±5.9[8] km/s
Age2.76[7] Gyr
Other designations
k Vel, CD−36 5505, GJ 339.3, GJ 9293, HD 79940, HIP 45448, HR 3684, SAO 200163, WDS J09158-3725A,[9] k2 Vel[10]
Database references
SIMBADdata

HD 79940 is a single[11] star in the southern constellation of Vela. It has the Bayer designation of k Velorum; HD 79940 is the identifier from the Henry Draper Catalogue. This star has a yellow-white hue and is faintly visible to the naked eye as a point light source with an apparent visual magnitude of 4.63.[3] It is located at a distance of approximately 158 light-years from the Sun based on parallax, and is drifting further away with a radial velocity of +6 km/s.[3]

There has been some disagreement over the stellar classification of this star. In 1975, S. Maladora found a class of F5III, suggesting an evolved F-type star,[5] matching an earlier (1957) classification by A. de Vaucouleurs.[6] N. Houk assigned it a class of F3/5V in 1979, matching an F-type main-sequence star.[4] It has a high rate of spin with a projected rotational velocity of 117.2±5.9 km/s.[8] This may explain why it was incorrectly classified as a spectroscopic binary in 1972.[11]

There is a faint magnitude 14.50 companion at an angular separation of 11.3″ along a position angle of 126° from the brighter star. This was discovered by T. J. J. See in 1897.[12]

References

[edit]
  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. 1 2 3 4 5 6 7 8 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. Gaia DR2 record for this source at VizieR.
  3. 1 2 3 4 5 6 7 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, S2CID 119257644.
  4. 1 2 Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 3, Ann Arbor, Michigan: Department of Astronomy, University of Michigan, Bibcode:1982mcts.book.....H.
  5. 1 2 Malaroda, S. (August 1975), "Study of the F-type stars. I. MK spectral types.", Astronomical Journal, 80: 637–641, Bibcode:1975AJ.....80..637M, doi:10.1086/111786.
  6. 1 2 de Vaucouleurs, A. (1957). "Spectral types and luminosities of B, A and F southern stars". Monthly Notices of the Royal Astronomical Society. 117 (4): 449. Bibcode:1957MNRAS.117..449D. doi:10.1093/mnras/117.4.449.
  7. 1 2 3 David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
  8. 1 2 Reiners, Ansgar (January 2006), "Rotation- and temperature-dependence of stellar latitudinal differential rotation", Astronomy and Astrophysics, 446 (1): 267–277, arXiv:astro-ph/0509399, Bibcode:2006A&A...446..267R, doi:10.1051/0004-6361:20053911, S2CID 8642707
  9. ↑ "HD 79940". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-28.
  10. ↑ Gould, Benjamin Apthorp (1879). "Uranometria Argentina catalog of bright southern stars". Resultados del Observatorio Nacional Argentino en Cordoba. 1. Buenos Aires. Bibcode:1879RNAO....1.....G. Retrieved 2012-05-08.
  11. 1 2 Kunzli, M.; North, P. (January 1998), "Are metallic A-F giants evolved AM stars? Rotation and rate of binaries among giant F stars", Astronomy and Astrophysics Supplement, 127 (2): 277–294, arXiv:astro-ph/9710226, Bibcode:1998A&AS..127..277K, doi:10.1051/aas:1998350, S2CID 7535170.
  12. ↑ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
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