12 Hydrae
  | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Hydra |
| Right ascension | 08h 46m 22.54441s |
| Declination | −13° 32′ 51.8051″ |
| Apparent magnitude (V) | 4.32 |
| Characteristics | |
| Evolutionary stage | red giant branch |
| Spectral type | G8 IIIb CN-1 |
| B−V color index | 0.900±0.015 |
| Astrometry | |
| Radial velocity (Rv) | −8.5±0.7 km/s |
| Proper motion (μ) | RA: +10.316 mas/yr Dec.: −15.012 mas/yr |
| Parallax (π) | 15.8840±0.3987 mas |
| Distance | 205 ± 5 ly (63 ± 2 pc) |
| Absolute magnitude (MV) | +0.26 |
| Orbit | |
| Primary | Aa |
| Secondary | Ab |
| Period (P) | 1,592±806 d |
| Semi-major axis (a) | 0.0116±0.057″ |
| Eccentricity (e) | 0.40±0.26 |
| Inclination (i) | 58±10° |
| Longitude of the node (Ω) | 91±16° |
| Periastron epoch (T) | 49,194±664 |
| Argument of periastron (ω) (secondary) | 103±34° |
| Details | |
| Mass | 1.83 M☉ |
| Radius | 10.8 R☉ |
| Luminosity | 71 L☉ |
| Surface gravity (log g) | 3.13 cgs |
| Temperature | 5,105 K |
| Metallicity [Fe/H] | −0.01 dex |
| Rotational velocity (v sin i) | 4.6±0.2 km/s |
| Age | 410 Myr |
| Other designations | |
| D Hya, 12 Hya, BD−13°2673, HD 74918, HIP 43067, HR 3484, SAO 154622, WDS J08464-1333 | |
| Database references | |
| SIMBAD | data |
12 Hydrae is a probable astrometric binary star system located 205 light years away from the Sun in the equatorial constellation of Hydra. It has the Bayer designation D Hydrae; 12 Hydrae is the Flamsteed designation. This system is visible to the naked eye as a faint, yellow-hued star with a combined apparent visual magnitude of 4.32. It is moving closer to the Earth with a heliocentric radial velocity of −8.5 km/s.
This was found to be a double star by R. A. Rossiter in 1953, with the magnitude 13.7 companion having an angular separation of 26.8″ along a position angle of 266°, as of 2016. The brighter, magnitude 4.32 component A is a spectroscopic binary. As of 2009, the orbital solution for this pair is of low quality, giving a period of roughly 4 years and an eccentricity of around 0.4.
The primary component is an aging giant star with a stellar classification of G8 IIIb CN-1, where the suffix notation indicates an underabundance of the cyanogen molecule. It is 410 million years old with 1.8 times the mass of the Sun. After exhausting the hydrogen at its core and evolving off the main sequence, the star has swollen to 11 times the Sun's radius. It is radiating 71 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 5,105 K.
References
- 1 2 3 4 5 6 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.
- 1 2 3 4 5 6 7 8 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- 1 2 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373
- 1 2 Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: A116, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, S2CID 53666672.
- 1 2 Hartkopf, W. I.; et al. (June 30, 2006), Sixth Catalog of Orbits of Visual Binary Stars, United States Naval Observatory, archived from the original on 2017-08-01, retrieved 2017-06-02.
- 1 2 3 4 Khalatyan, A.; Anders, F.; Chiappini, C.; Queiroz, A. B. A.; Nepal, S.; Dal Ponte, M.; Jordi, C.; Guiglion, G.; Valentini, M.; Torralba Elipe, G.; Steinmetz, M.; Pantaleoni-González, M.; Malhotra, S.; Jiménez-Arranz, Ó.; Enke, H.; Casamiquela, L.; Ardèvol, J. (2024). "Transferring spectroscopic stellar labels to 217 million Gaia DR3 XP stars with SHBoost". Astronomy and Astrophysics. 691: A98. arXiv:2407.06963. Bibcode:2024A&A...691A..98K. doi:10.1051/0004-6361/202451427.
- 1 2 3 4 Stassun, Keivan G.; et al. (2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467.
- 1 2 Fetherolf, Tara; Pepper, Joshua; Simpson, Emilie; Kane, Stephen R.; Močnik, Teo; English, John Edward; Antoci, Victoria; Huber, Daniel; Jenkins, Jon M.; Stassun, Keivan; Twicken, Joseph D.; Vanderspek, Roland; Winn, Joshua N. (2023). "Variability Catalog of Stars Observed during the TESS Prime Mission". The Astrophysical Journal Supplement Series. 268 (1): 4. arXiv:2208.11721. Bibcode:2023ApJS..268....4F. doi:10.3847/1538-4365/acdee5.
- 1 2 "12 Hya". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved May 1, 2019.
- ↑ 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.
- ↑ Rossiter, R. A. (February 1953), "Seventh list of new Southern double stars found at the Lamont-Hussey Observatory of the University of Michigan at Bloemfontein, South Africa.", Astronomical Journal, 58: 29–30, Bibcode:1953AJ.....58...29R, doi:10.1086/106804.
