| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Hydra1 |
| Right ascension | 08h 40m 01.47182s2 |
| Declination | −12° 28′ 31.3433″2 |
| Apparent magnitude (V) | 4.981 |
| Characteristics | |
| Evolutionary stage | red giant branch3 |
| Spectral type | K3 III4 |
| B−V color index | 1.415±0.0011 |
| Astrometry | |
| Radial velocity (Rv) | −7.8±0.65 km/s |
| Proper motion (μ) | RA: −81.6192 mas/yr Dec.: −1.6462 mas/yr |
| Parallax (π) | 8.7394±0.1769 mas2 |
| Distance | 373 ± 8 ly (114 ± 2 pc) |
| Absolute magnitude (MV) | −0.401 |
| Details | |
| Radius | 32.7+0.5 −2.62 R☉ |
| Luminosity | 267±62 L☉ |
| Surface gravity (log g) | 1.916 cgs |
| Temperature | 4,080+173 −302 K |
| Metallicity [Fe/H] | −0.216 dex |
| Other designations | |
| a Hya, 6 Hya, BD−11°2420, HD 73840, HIP 42509, HR 3431, SAO 1545157 | |
| Database references | |
| SIMBAD | data |
6 Hydrae is a single8 star in the equatorial constellation of Hydra, located 373 light-years away from the Sun.2 It has the Bayer designation a Hydrae; 6 Hydrae is the Flamsteed designation. This object is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.98.1 It is moving closer to the Earth with a heliocentric radial velocity of −8 km/s.5 Eggen (1995) listed it as a proper motion candidate for membership in the IC 2391 supercluster.9
This is an aging giant star with a stellar classification of K3 III,4 which indicates it has exhausted the hydrogen at its core and evolved away from the main sequence. As a consequence, it has expanded to 332 times the radius of the Sun. The star is radiating 2672 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,080 K.2
References
References
- 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. XHIP record for this object at VizieR.
- 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.
- McWilliam, Andrew (1990). "High-Resolution Spectroscopic Survey of 671 GK Giants. I. Stellar Atmosphere Parameters and Abundances". The Astrophysical Journal Supplement Series. 74: 1075. Bibcode:1990ApJS...74.1075M. doi:10.1086/191527.
- 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.
- 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.
- 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, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527.
- "6 Hya". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-04-23.
- 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.
- Eggen, Olin J. (December 1995), "Reality Tests of Superclusters in the Young Disk Population", Astronomical Journal, 110: 2862, Bibcode:1995AJ....110.2862E, doi:10.1086/117734.