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 mas[1] |
| Distance | 207 ± 4 ly (63 ± 1 pc) |
| Absolute magnitude (MV) | −0.18[2] |
| Details | |
| Mass | 3.2[5] M☉ |
| Radius | 12[6] R☉ |
| Luminosity | 128.02[2] L☉ |
| Surface gravity (log g) | 2.50[7] cgs |
| Temperature | 5,210[7] K |
| Metallicity [Fe/H] | −0.03[7] dex |
| Rotational velocity (v sin i) | 5.8[8] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
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[edit]
- ^ a b c d e f 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.
- ^ a b c d e f 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.
- ^ a b 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.
- ^ a b 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, S2CID 59451347, A61.
- ^ a b 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.
- ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
- ^ a b c d 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.
- ^ 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.
- ^ "HD 74772". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-08-07.
- ^ 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, S2CID 14878976.
- ^ Maggio, A.; et al. (1993), "Soft X-ray Emission and Spectra of Evolved Stars from ROSAT Pointed Observations", in Linsky, Jeffrey L.; Serio, Salvatore (eds.), Physics of Solar and Stellar Coronae: G. S. Vaiana Memorial Symposium, held 22-26 June, 1992, in Palermo, Italy, Astrophysics and Space Science Library, vol. 183, Dordrecht, The Netherlands: Kluwer Academoc Publishers, p. 365, Bibcode:1993ASSL..183..365M, doi:10.1007/978-94-011-1964-1_47.
- ^ 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.
