Triple star system in the constellation Lacerta
HD 211073 is a triple star [ 8] system in the northern constellation Lacerta , located around 580[ 1] light years from the Sun. It is visible to the naked eye as a faint orange-hued star with a baseline apparent visual magnitude of 4.50.[ 2] The system is moving closer to the Earth with a heliocentric radial velocity of −11.7 km/s.[ 5]
The primary member, designated component Aa, is an evolved giant star with a stellar classification of K2.5 III[ 4] that is most likely (98% chance) on the horizontal branch .[ 6] It is a suspected variable star that ranges in magnitude from 4.49 down to 4.55.[ 3] This star is around a billion years old with 2.2 times the mass of the Sun and has expanded to 46 times the Sun's radius . It is radiating about 574 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,180 K.[ 6]
As of 2005, the inner pair of stars (Aa + Ab) in this system had an angular separation of 0.20″ along a position angle (PA) of 170°. The magnitude 8.15 component Ac was separated from Aa by 0.30″ with a PA of 27°, as of 2010. As of 2015, the magnitude 10.60 visual companion , designated component B, was separated from the primary by 30.50″ along a PA of 190°.[ 9]
References
^ a b c d e f 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 .
^ a b c 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 .
^ a b Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports , 5.1, 61 (1): 80– 88, Bibcode :2017ARep...61...80S , doi :10.1134/S1063772917010085 , S2CID 125853869 .
^ a b 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 .
^ a b c d De Medeiros, J. R.; Mayor, M. (1999), "A catalog of rotational and radial velocities for evolved stars", Astronomy and Astrophysics Supplement Series , 139 (3): 433, arXiv :astro-ph/0608248 , Bibcode :1999A&AS..139..433D , doi :10.1051/aas:1999401 .
^ a b c Stock, Stephan; et al. (August 2018), "Precise radial velocities of giant stars. X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search", Astronomy & Astrophysics , 616 : 15, arXiv :1805.04094 , Bibcode :2018A&A...616A..33S , doi :10.1051/0004-6361/201833111 , S2CID 119361866 , A33.
^ "HD 211073" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-02-02 .
^ 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 .
^ Mason, Brian D.; et al. (December 2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal , 122 (6): 3466– 3471, Bibcode :2001AJ....122.3466M , doi :10.1086/323920 .