Astronomy:Mu Hydrae
From HandWiki
Short description: Star in the constellation Hydra
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Hydra |
| Right ascension | 10h 26m 05.42630s[1] |
| Declination | −14° 19′ 56.2675″[1] |
| Apparent magnitude (V) | 3.83[2] |
| Characteristics | |
| Spectral type | K4 III[3] |
| U−B color index | +1.83[2] |
| B−V color index | +1.47[2] |
| Variable type | Suspected[4] |
| Astrometry | |
| Radial velocity (Rv) | +40.81±0.36[5] km/s |
| Proper motion (μ) | RA: −129.17[1] mas/yr Dec.: −79.76[1] mas/yr |
| Parallax (π) | 13.93 ± 0.18[1] mas |
| Distance | 234 ± 3 ly (71.8 ± 0.9 pc) |
| Absolute magnitude (MV) | −0.45[6] |
| Details[5] | |
| Radius | 45 R☉ |
| Luminosity | 332[6] L☉ |
| Surface gravity (log g) | 1.5 cgs |
| Temperature | 3,999±8 K |
| Metallicity [Fe/H] | −0.12 dex |
| Rotational velocity (v sin i) | 6.0 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
μ Hydrae, Latinised as Mu Hydrae, is a solitary,[8] orange-hued star in the equatorial constellation of Hydra. It is visible to the naked eye with an apparent visual magnitude of 3.83.[2] Positioned just 1.8° to the south-southwest is the planetary nebula NGC 3242.[9] Mu Hydrae has an annual parallax shift of 13.93 mas,[1] which yields a distance estimate of 234 light years.
This is an evolved K-type giant star with a stellar classification of K4 III,[3] having used up its core hydrogen and has expanded to around 45 times the radius of the Sun.[5] It is a suspected variable star, with a brightness that varies about 0.03 in magnitude.[4] The relatively cool outer atmosphere has an effective temperature of 3999 K.[5]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode: 1986EgUBV........0M.
- ↑ 3.0 3.1 Houk, N.; Smith-Moore, M. (1988), University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Declinations -26°.0 to -12°.0, 4, Department of Astronomy, University of Michigan, Bibcode: 1988mcts.book.....H.
- ↑ 4.0 4.1 Samus, N. N. et al. (2009), "General Catalogue of Variable Stars", Vizier Online Data Catalog 1, Bibcode: 2009yCat....102025S.
- ↑ 5.0 5.1 5.2 5.3 Massarotti, Alessandro et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal 135 (1): 209–231, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M.
- ↑ 6.0 6.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ "* mu. Hya". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+mu.+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.
- ↑ O'Meara, Steve (2007), Herschel 400 Observing Guide, Cambridge University Press, p. 107, ISBN 978-0521858939, https://books.google.com/books?id=Nyh9fAC_tpIC&pg=PA107.
 |  |
