Location of ν Hydri (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydrus |
| Right ascension | 02 50 28.45915 |
| Declination | −75° 04′ 00.9969″ |
| Apparent magnitude (V) | 4.76 |
| Characteristics | |
| Spectral type | K3III |
| U−B color index | +1.56 |
| B−V color index | +1.33 |
| Astrometry | |
| Radial velocity (Rv) | +3.09±0.16 km/s |
| Proper motion (μ) | RA: −33.392 mas/yr Dec.: −27.286 mas/yr |
| Parallax (π) | 9.8538 ± 0.1433 mas |
| Distance | 331 ± 5 ly (101 ± 1 pc) |
| Absolute magnitude (MV) | −0.33 |
| Details | |
| Mass | 3.5 or 1.79 M☉ |
| Radius | 21.23+3.23 −4.50 R☉ |
| Luminosity | 183.8±3.2 L☉ |
| Surface gravity (log g) | 3.30 cgs |
| Temperature | 4,612+584 −315 K |
| Metallicity | −1.52 dex |
| Rotation | 50 d |
| Rotational velocity (v sin i) | 1.3 km/s |
| Age | 2.38 Gyr |
| Other designations | |
| ν Hyi, CPD−75°204, FK5 2199, GC 3463, HD 18293, HIP 13244, HR 872, SAO 255929 | |
| Database references | |
| SIMBAD | data |
ν Hydri, Latinized as Nu Hydri, is a single star in the southern circumpolar constellation of Hydrus. It is orange-hued and faintly visible to the naked eye with an apparent visual magnitude of 4.76. This object is located approximately 331 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +3 km/s. It is a member of the Ursa Major Moving Group of stars that share a common motion through space.
This is an aging giant star with a stellar classification of K3III. With the supply of hydrogen at its core exhausted, the star has expanded and cooled. At present it has 21 times the girth of the Sun. It is 2.4 billion years old with estimates of its mass ranging from 1.8 to 3.5 times the mass of the Sun. The star is radiating 184 times the Sun's luminosity from its swollen photosphere at an effective temperature of 4,612 K.
References
- ^ 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.
- ^ 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. Vizier catalog entry
- ^ Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 1, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1975mcts.book.....H
- ^ Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42 (2): 443. Bibcode:2014JAVSO..42..443M.Vizier catalog entry
- ^ Gondoin, P. (December 2005), "The relation between X-ray activity and rotation in intermediate-mass G giants", Astronomy and Astrophysics, 444 (2): 531–538, Bibcode:2005A&A...444..531G, doi:10.1051/0004-6361:20053567.
- ^ Luck, R. Earle (2015). "Abundances in the Local Region. I. G and K Giants". The Astronomical Journal. 150 (3): 88. arXiv:1507.01466. Bibcode:2015AJ....150...88L. doi:10.1088/0004-6256/150/3/88. S2CID 118505114.
- ^ Soubiran, Caroline; Le Campion, Jean-François; Brouillet, Nathalie; Chemin, Laurent (2016). "The PASTEL catalogue: 2016 version". Astronomy & Astrophysics. 591: A118. arXiv:1605.07384. Bibcode:2016A&A...591A.118S. doi:10.1051/0004-6361/201628497. S2CID 119258214.
- De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (2014). "A catalog of rotational and radial velocities for evolved stars". Astronomy & Astrophysics. 561: A126. arXiv:1312.3474. Bibcode:2014A&A...561A.126D. doi:10.1051/0004-6361/201220762. S2CID 54046583. Vizier catalog entry
- "nu Hyi". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-30.
- 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.
- Chupina, N. V.; et al. (June 2006), "Kinematic structure of the corona of the Ursa Major flow found using proper motions and radial velocities of single stars", Astronomy and Astrophysics, 451 (3): 909–916, Bibcode:2006A&A...451..909C, doi:10.1051/0004-6361:20054009.
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