Astronomy:HD 79940
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Vela |
| Right ascension | 09h 15m 45.07943s[1] |
| Declination | −37° 24′ 47.3124″[1] |
| Apparent magnitude (V) | 4.63[2] |
| Characteristics | |
| Spectral type | F3/5V[3] or F5III[4][5] |
| B−V color index | 0.473±0.002[2] |
| Astrometry | |
| Radial velocity (Rv) | +5.8±2.8[2] km/s |
| Proper motion (μ) | RA: +14.128[1] mas/yr Dec.: −8.111[1] mas/yr |
| Parallax (π) | 20.5985 ± 0.1895[1] mas |
| Distance | 158 ± 1 ly (48.5 ± 0.4 pc) |
| Absolute magnitude (MV) | 1.12[2] |
| Details[6] | |
| Mass | 1.36[6] M☉ |
| Radius | 4.35+0.11 −0.19[1] R☉ |
| Luminosity | 28.427±0.305[1] L☉ |
| Surface gravity (log g) | 3.26±0.14[6] cgs |
| Temperature | 6,388+143 −76[1] K |
| Metallicity [Fe/H] | 0.20±0.15[2] dex |
| Rotational velocity (v sin i) | 117.2±5.9[7] km/s |
| Age | 2.76[6] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 79940 is a single[9] 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.[2] 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.[2]
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,[4] matching an earlier (1957) classification by A. de Vaucouleurs.[5] N. Houk assigned it a class of F3/5V in 1979, matching an F-type main-sequence star.[3] It has a high rate of spin with a projected rotational velocity of 117.2±5.9 km/s.[7] This may explain why it was incorrectly classified as a spectroscopic binary in 1972.[9]
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.[10]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, 3, Ann Arbor, Michigan: Department of Astronomy, University of Michigan, Bibcode: 1982mcts.book.....H.
- ↑ 4.0 4.1 Malaroda, S. (August 1975), "Study of the F-type stars. I. MK spectral types.", Astronomical Journal 80: 637–641, doi:10.1086/111786, Bibcode: 1975AJ.....80..637M.
- ↑ 5.0 5.1 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. doi:10.1093/mnras/117.4.449. Bibcode: 1957MNRAS.117..449D.
- ↑ 6.0 6.1 6.2 6.3 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, doi:10.1088/0004-637X/804/2/146, Bibcode: 2015ApJ...804..146D.
- ↑ 7.0 7.1 Reiners, Ansgar (January 2006), "Rotation- and temperature-dependence of stellar latitudinal differential rotation", Astronomy and Astrophysics 446 (1): 267–277, doi:10.1051/0004-6361:20053911, Bibcode: 2006A&A...446..267R
- ↑ "HD 79940". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+79940.
- ↑ 9.0 9.1 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, doi:10.1051/aas:1998350, Bibcode: 1998A&AS..127..277K.
- ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466–3471, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M.
 |  |
