Mu Hydrae
Star in the constellation Hydra
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
^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics , 474 (2): 653–664, arXiv :0708.1752 , Bibcode :2007A&A...474..653V , doi :10.1051/0004-6361:20078357 , S2CID 18759600 .
^ a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data , SIMBAD , Bibcode :1986EgUBV........0M .
^ a b 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 , vol. 4, Department of Astronomy, University of Michigan , Bibcode :1988mcts.book.....H .
^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009), "General Catalogue of Variable Stars", Vizier Online Data Catalog , 1 , Bibcode :2009yCat....102025S .
^ a b c d 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, Bibcode :2008AJ....135..209M , doi :10.1088/0004-6256/135/1/209 , S2CID 121883397 .
^ a b 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 .
^ "* mu. Hya" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2017-01-06 .
^ 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 .
^ O'Meara, Steve (2007), Herschel 400 Observing Guide , Cambridge University Press , p. 107, ISBN 978-0521858939 .