11 Librae
Star in the constellation Libra
11 Librae is a single,[ 5] fifth-magnitude star in the southern zodiac constellation of Libra . It is faintly visible to the naked eye with an apparent visual magnitude is 4.93.[ 2] The star is moving further from the Sun with a heliocentric radial velocity of +83.6 km/s.[ 3] The distance to this star, as estimated from its annual parallax shift of 14.92± 0.40 mas ,[ 1] is about 219 light years .
This star has a stellar classification of K0 III/IV,[ 6] indicating the spectrum displays mixed traits of a giant /subgiant K-type star . Alves (2000) and Afşar et al. (2012) classify it as a red clump star, which means it is an evolved star at the cool end of the horizontal branch and is generating energy through helium fusion in its core region .[ 7] [ 8] It is about five billion years old and is spinning with a projected rotational velocity of 4 km/s. The star has 1.1 times the mass of the Sun and has expanded to over 10 times the Sun's radius . It is radiating around 59 times the Sun's radius from its enlarged photosphere at an effective temperature of about 4,749 K.[ 3]
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 e 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 c d Jofré, E.; et al. (February 2015), "Stellar parameters and chemical abundances of 223 evolved stars with and without planets", Astronomy & Astrophysics , 574 : 46, arXiv :1410.6422 , Bibcode :2015A&A...574A..50J , doi :10.1051/0004-6361/201424474 , S2CID 53666931 , A50.
^ "11 Lib" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2018-03-01 .
^ 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 .
^ Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey , 5 , Bibcode :1999MSS...C05....0H .
^ Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal , 539 (2): 732−741, arXiv :astro-ph/0003329 , Bibcode :2000ApJ...539..732A , doi :10.1086/309278 , S2CID 16673121 .
^ Afşar, M.; et al. (July 2012), "Chemical Compositions of Thin-disk, High-metallicity Red Horizontal-branch Field Stars", The Astronomical Journal , 144 (1): 20, arXiv :1205.3659 , Bibcode :2012AJ....144...20A , doi :10.1088/0004-6256/144/1/20 , S2CID 119249237 , 20.