Astronomy:51 Hydrae
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Hydra |
| Right ascension | 14h 23m 05.77393s[1] |
| Declination | −27° 45′ 14.4609″[1] |
| Apparent magnitude (V) | 4.78[2] |
| Characteristics | |
| Evolutionary stage | giant |
| Spectral type | K4 III[3] |
| B−V color index | 1.300±0.040[2] |
| Astrometry | |
| Radial velocity (Rv) | 19.7±0.9[2] km/s |
| Proper motion (μ) | RA: −202.476[1] mas/yr Dec.: −117.186[1] mas/yr |
| Parallax (π) | 19.2042 ± 0.2252[1] mas |
| Distance | 170 ± 2 ly (52.1 ± 0.6 pc) |
| Absolute magnitude (MV) | 1.36[2] |
| Details | |
| Mass | 1.31[4] M☉ |
| Radius | 13.47+0.48 −1.26[1] R☉ |
| Luminosity | 54.9+0.8 −1.5[1] L☉ |
| Surface gravity (log g) | 2.25[5] cgs |
| Temperature | 4,255±31[4] K |
| Metallicity [Fe/H] | 0.08[5] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
51 Hydrae is a single[7] star in the equatorial constellation of Hydra,[6] located 170 light years away from the Sun.[1] It has the Bayer designation k Hydrae; 51 Hydrae is the Flamsteed designation.[6] This object is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.78. It is moving further from the Earth with a heliocentric radial velocity of +20 km/s.[2] Eggen (1971) listed it as a member of the η Cephei group of old-disk stars.[8]
This is an evolved giant star with a stellar classification of K4 III,[3] which indicates it has exhausted the supply of hydrogen at its core and expanded off the main sequence. It has 1.31[4] times the mass of the Sun but has swollen to 13.5[1] times the Sun's radius. The star is radiating 55[1] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,255 K.[4]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 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 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 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins Catalog of Revised MK Types for the Cooler Stars", The Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode: 1989ApJS...71..245K.
- ↑ 4.0 4.1 4.2 4.3 Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal 150 (3): 88, doi:10.1088/0004-6256/150/3/88, Bibcode: 2015AJ....150...88L
- ↑ 5.0 5.1 McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series 74: 1075–1128, doi:10.1086/191527, Bibcode: 1990ApJS...74.1075M.
- ↑ 6.0 6.1 6.2 "k Hya". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=k+Hya.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Eggen, O. J. (June 1971), "The ζ Herculis, σ Puppis, ∈ Indi, and η Cephei Groups of Old Disk Population Stars", Publications of the Astronomical Society of the Pacific 83 (493): 251, doi:10.1086/129119, Bibcode: 1971PASP...83..251E.
 |  |
