HD 89998 (r Velorum) is a single[8] star in the southern constellation of Vela. It is a faint star but visible to the naked eye with an apparent visual magnitude of 4.82.[2] The distance to HD 89998, as determined from its annual parallax shift of 15.9 mas,[1] is 205 light years. The star is moving further from the Earth with a heliocentric radial velocity of +21 km/s,[4] having come within 140 ly some 1.552 million years ago.[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Vela |
| Right ascension | 10h 22m 19.58477s[1] |
| Declination | −41° 38′ 59.8592″[1] |
| Apparent magnitude (V) | 4.82[2] |
| Characteristics | |
| Spectral type | K1 III[3] |
| B−V color index | 1.095±0.055[2] |
| Astrometry | |
| Radial velocity (Rv) | +20.9±0.8[4] km/s |
| Proper motion (μ) | RA: −27.664[1] mas/yr Dec.: +60.090[1] mas/yr |
| Parallax (π) | 15.9154 ± 0.1375 mas[1] |
| Distance | 205 ± 2 ly (62.8 ± 0.5 pc) |
| Absolute magnitude (MV) | 0.84[2] |
| Details | |
| Radius | 11.6[5] R☉ |
| Luminosity | 54.04[6] L☉ |
| Temperature | 4,812[6] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an evolved giant star with a stellar classification of K1 III.[3] The measured angular diameter of this star, after correcting for limb darkening, is 1.72±0.02 mas.[9] At the estimated distance of this star, this yields a physical size of 11.6 times the radius of the Sun.[5] It is radiating 54[6] times the Sun's luminosity from its enlarged photosphere at en effective temperature of 4,812 K.[6]
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 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 Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
- ^ 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 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 McDonald, I.; et al. (2012), "Fundamental parameters and infrared excesses of Hipparcos stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–357, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
- ^ "HD 85622". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-08-08.
- ^ 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.
- ^ 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.
