Phi Geminorum
Binary star system in the constellation Gemini
Phi Geminorum , Latinized from φ Geminorum , is a binary star [6] in the constellation Gemini , to the southeast of Pollux . It is visible to the naked eye with an apparent visual magnitude of 4.95.[2] Based upon an annual parallax shift of 14.66 mas ,[1] this system is located around 220 light years from the Sun .
The two components of this system have a circular orbit with a period of 582 days.[6] The primary component is an A-type main sequence star with a stellar classification of A3 V.[3] It is around 600 million years old and spinning relatively rapidly with a projected rotational velocity of 165[9] km/s. This rate of spin is giving the star an oblate shape with an equatorial bulge that is 6% larger than the polar radius.[3] The star has nearly double the mass of the Sun and radiates 36.5[8] times the solar luminosity from its outer atmosphere at an effective temperature of 8,551[7] K.
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^ a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data , SIMBAD , Bibcode :1986EgUBV........0M .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 c van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review , 20 (1): 51, arXiv :1204.2572 , Bibcode :2012A&ARv..20...51V , doi :10.1007/s00159-012-0051-2 , S2CID 119273474 .
^ Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication , Carnegie Institute of Washington, D.C., Bibcode :1953GCRV..C......0W .
^ 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 Abt, Helmut A. (August 2005), "Observed Orbital Eccentricities", The Astrophysical Journal , 629 (1): 507–511, Bibcode :2005ApJ...629..507A , doi :10.1086/431207 .
^ a b c d e David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal , 804 (2): 146, arXiv :1501.03154 , Bibcode :2015ApJ...804..146D , doi :10.1088/0004-637X/804/2/146 , S2CID 33401607 .
^ a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society , 427 (1): 343–57, arXiv :1208.2037 , Bibcode :2012MNRAS.427..343M , doi :10.1111/j.1365-2966.2012.21873.x , S2CID 118665352 .
^ a b Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics , 463 (2): 671–682, arXiv :astro-ph/0610785 , Bibcode :2007A&A...463..671R , doi :10.1051/0004-6361:20065224 , S2CID 18475298 .
^ "* phi Gem" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2016-12-08 .{{cite web }}
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