HD 21447
Probable binary star in the constellation Camelopardalis
HD 21447 is a probable binary star [ 9] system located in the constellation Camelopardalis . The star is also known as HR 1046 . It can be viewed with the naked eye, having an apparent visual magnitude of 5.09.[ 2] Based upon an annual parallax shift of 16.42± 0.29 mas ,[ 1] it is located some 199 light years from the Sun. It is a candidate for membership in the Ursa Major Moving Group .[ 10]
The primary component is A-type main-sequence star with a stellar classification of A1 Va.[ 3] It is around 146[ 7] million years old and is spinning with a projected rotational velocity of 182 km/s.[ 7] The star has an estimated 2.32[ 5] times the mass of the Sun and about 1.9[ 6] times the Sun's radius . It is radiating around 32[ 2] times the Sun's luminosity from its photosphere at an effective temperature of 10,049 K.[ 7] The companion is visual magnitude 9.4 star at an angular separation of 14.8″ .[ 9]
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 f 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 Gray, R. O.; Garrison, R. F. (December 1987), "The Early A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation", Astrophysical Journal Supplement , 65 : 581, Bibcode :1987ApJS...65..581G , doi :10.1086/191237 .
^ 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 De Rosa, R. J.; et al. (January 2014), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society , 437 (2): 1216–1240, arXiv :1311.7141 , Bibcode :2014MNRAS.437.1216D , doi :10.1093/mnras/stt1932 , S2CID 88503488 .
^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics , 367 (Third ed.): 521–524, arXiv :astro-ph/0012289 , Bibcode :2001A&A...367..521P , doi :10.1051/0004-6361:20000451 , S2CID 425754 .
^ a b c d e f g 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 .
^ "HD 21447" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2018-05-16 .
^ a b 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 .
^ King, Jeremy R.; et al. (2003), "Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group" , The Astronomical Journal , 125 (4): 1980, Bibcode :2003AJ....125.1980K , doi :10.1086/368241 .
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