HD 85859 is a single[7] star in the equatorial constellation of Hydra. It has an apparent visual magnitude of 4.88,[2] which is bright enough to be visible to the naked eye. The distance to this star, as estimated from its annual parallax shift of 12.6 mas,[1] is 259 light years. It is moving away from the Earth with a heliocentric radial velocity of 50.5 km/s.[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 09h 54m 12.32596s[1] |
| Declination | −25° 55′ 56.3631″[1] |
| Apparent magnitude (V) | 4.88[2] |
| Characteristics | |
| Spectral type | K2 III CN0.5[3] |
| B−V color index | 1.23[2] |
| Astrometry | |
| Radial velocity (Rv) | 50.5[2] km/s |
| Proper motion (μ) | RA: −187.764[1] mas/yr Dec.: 52.746[1] mas/yr |
| Parallax (π) | 12.5809 ± 0.2161 mas[1] |
| Distance | 259 ± 4 ly (79 ± 1 pc) |
| Absolute magnitude (MV) | −0.23[4] |
| Details | |
| Mass | 1.55[2] M☉ |
| Luminosity | 178[2] L☉ |
| Surface gravity (log g) | 2.35[5] cgs |
| Temperature | 4,415±25[2] K |
| Metallicity [Fe/H] | −0.03[5] dex |
| Age | 4.34[2] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The stellar classification of the visible component is K2 III CN0.5,[3] which matches an evolved K-type giant star with a mild overabundance of CN in the atmosphere. At the age of 4.34[2] billion years, it is a red clump star, which indicates it is on the horizontal branch and is generating energy through helium fusion at its core.[8] The star has 1.55[2] times the mass of the Sun and is radiating 178[2] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,415 K.[2]
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.
- ^ a b c d e f g h i j k l m Luck, R. Earle (2015). "Abundances in the Local Region. I. G and K Giants". Astronomical Journal. 150 (3). 88. arXiv:1507.01466. Bibcode:2015AJ....150...88L. doi:10.1088/0004-6256/150/3/88. S2CID 118505114.
- ^ a b Keenan, P.; McNeil, R. (October 1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245–266, Bibcode:1989ApJS...71..245K, doi:10.1086/191373
- ^ 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 Soubiran, C.; et al. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247, S2CID 118362423.
- ^ "HD 85859". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-26.
- ^ 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.
- ^ Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329, Bibcode:2000ApJ...539..732A, doi:10.1086/309278, S2CID 16673121.