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HD 211073 is a triple star system in the northern constellation Lacerta, located around 580 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. The system is moving closer to the Earth with a heliocentric radial velocity of −11.7 km/s.

The primary member, designated component Aa, is an evolved giant star with a stellar classification of K2.5 III that is most likely (98% chance) on the horizontal branch. It is a suspected variable star that ranges in magnitude from 4.49 down to 4.55. 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.

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°.

References

1. ^ 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.
2. ^ 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.
3. ^ 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.
4. ^ 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.
5. ^ 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.
6. ^ 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.
7. "HD 211073". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-02-02.
8. 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.
9. 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.

v t e Constellation of Lacerta
List of stars in Lacerta Lacerta in Chinese astronomy
Stars	Bayer α β Flamsteed 1 2 4 5 6 8 9 10 11 12 13 14 15 16 Variable U AR CP DI DK EV EW V424 HR 8485 Other ADS 16402 MWC 656
Exoplanets HAT-P-1b
Star clusters NGC 7209 NGC 7243
Galaxies	NGC 7250 Other BL 3C 449 3C 452
Category

• K-type giants
• Horizontal-branch stars
• Suspected variables
• Triple star systems
• Lacerta
• Durchmusterung objects
• Henry Draper Catalogue objects
• Hipparcos objects
• Bright Star Catalogue objects