HD 111456
Star in the constellation Ursa Major
HD 111456 is a yellow-white hued star in the northern circumpolar constellation of Ursa Major . It is dimly visible to the naked eye, having an apparent visual magnitude of 5.85.[2] Based upon an annual parallax shift of 38.2 mas as seen from Earth, it is located about 85 light years from the Sun . The star is moving closer to the Sun with a radial velocity of −18 km/s .[4] HD 111456 is a nucleus cluster member of the Ursa Major Moving Group , a set of stars that are moving through space with a similar heading and velocity. Six other stars in the nucleus of the group are prominent members of the Big Dipper asterism .[3]
The stellar classification for this star is F7 V,[3] indicating that it is an ordinary F-type main-sequence star . It is young, around 300−400 million years of age, and is spinning with a relatively high projected rotational velocity of 41.5 km/s.[5] This is one of the most active F-type stars known, and it is a strong emitter of X-rays [5] and an extreme UV source. It is an astrometric binary with a period of four years and a mass ratio of 0.5. Hence, the companion may be a young white dwarf star.[8]
References
^ a b c d e 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 d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory , 4 (99): 99, Bibcode :1966CoLPL...4...99J .
^ a b c Levato, H.; Abt, H. A. (August 1978), "Spectral types in the Ursa Major stream", Publications of the Astronomical Society of the Pacific , 90 : 429−433, Bibcode :1978PASP...90..429L , doi :10.1086/130352 .
^ a b de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics , 546 : 14, arXiv :1208.3048 , Bibcode :2012A&A...546A..61D , doi :10.1051/0004-6361/201219219 , S2CID 59451347 , A61.
^ a b c d e f g h Freire Ferrero, R.; et al. (January 2004), "Magnetic activity in HD 111456, a young F5-6 main-sequence star", Astronomy and Astrophysics , 413 (2): 657−667, Bibcode :2004A&A...413..657F , doi :10.1051/0004-6361:20031565 .
^ 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 .
^ "HR 4867" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2017-10-25 .{{cite web }}
: CS1 maint: postscript (link )
^ Goldin, A.; Makarov, V. V. (September 2006), "Unconstrained Astrometric Orbits for Hipparcos Stars with Stochastic Solutions", The Astrophysical Journal Supplement Series , 166 (1): 341−350, arXiv :astro-ph/0606293 , Bibcode :2006ApJS..166..341G , doi :10.1086/505939 , S2CID 15673734 .