HD 57821 is a single[9] star in the southern constellation of Canis Major. It has a blue-white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.94.[2] Based on parallax measurements, the distance to this object is approximately 480 light years. It is drifting further away with a radial velocity of +33 km/s, having come to within 71 light-years some 4.3 million years ago.[2]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 07h 22m 13.52901s[1] |
| Declination | −19° 00′ 59.7646″[1] |
| Apparent magnitude (V) | 4.94[2] |
| Characteristics | |
| Evolutionary stage | Main sequence[3] |
| Spectral type | B5 II/III[4] or B7 IV[5] |
| B−V color index | −0.039±0.024[2] |
| Astrometry | |
| Radial velocity (Rv) | +32.9±1.6[2] km/s |
| Proper motion (μ) | RA: −1.69[1] mas/yr Dec.: +6.91[1] mas/yr |
| Parallax (π) | 6.78 ± 0.26 mas[1] |
| Distance | 480 ± 20 ly (147 ± 6 pc) |
| Absolute magnitude (MV) | −0.90[2] |
| Details | |
| Mass | 4.12±0.08[3] M☉ |
| Radius | 4.7[6] R☉ |
| Luminosity | 489+43 −40[3] L☉ |
| Temperature | 12,445±86[3] K |
| Rotational velocity (v sin i) | 116[3] km/s |
| Age | 291[7] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The stellar classification of this star is B5 II/III,[4] which matches the spectrum of a giant/bright giant although stellar models suggest it may still be on the main sequence.[3] It has over four[3] times the mass of the Sun and is 291[7] million years old. The star has a high rate of spin, showing a projected rotational velocity of 116 km/s.[3] It is radiating around 489[3] times the luminosity of the Sun from its photosphere at an effective temperature of 12,445 K.[3]
References
edit- ^ 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, S2CID 18759600.
- ^ 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 c d e f g h i j Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
- ^ a b Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
- ^ Cowley, A. (November 1972), "Spectral classification of the bright B8 stars", Astronomical Journal, 77: 750–755, Bibcode:1972AJ.....77..750C, doi:10.1086/111348.
- ^ Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (2) (Third ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754
- ^ a b Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters, 38 (11): 694–706, arXiv:1606.09028, Bibcode:2012AstL...38..694G, doi:10.1134/S1063773712110035, S2CID 119108982.
- ^ "HD 57821". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-01-18.
- ^ 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, S2CID 14878976.