Star in the constellation Norma
θ Normae , Latinised as Theta Normae , is a binary star system in the constellation Norma . It has an apparent visual magnitude of 5.13[ 2] and is visible to the naked eye as a faint, blue-white-hued point of light. Based upon an annual parallax shift of 9.27 mas as seen from Earth,[ 5] this system is located about 352 light-years from the Sun . At that distance, the visual magnitude of these stars is diminished by an extinction of 0.45 due to interstellar dust .[ 12]
Chini et al. (2012) identified this as a single-lined spectroscopic binary system.[ 13] The visible component is a B-type main-sequence star with a stellar classification of B8 V.[ 3] It is about 17[ 7] million tears old and is spinning rapidly with a projected rotational velocity of 251 km/s.[ 10] The star has 3.6[ 7] times the mass of the Sun and 3.05[ 8] times the Sun's radius . It is radiating about 184 times the Sun's luminosity from its photosphere at an effective temperature of 12,341 K .[ 9] This system displays an infrared excess , suggesting a debris disk is orbiting at a mean radius of 21.8 AU with a temperature of 220 K.[ 8]
References
^ a b 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 Corben, P. M.; Stoy, R. H. (1968), "Photoelectric Magnitudes and Colours for Bright Southern Stars", Monthly Notes of the Astronomical Society of Southern Africa , 27 : 11, Bibcode :1968MNSSA..27...11C .
^ a b Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars , vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode :1978mcts.book.....H .
^ 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 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 .
^ 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 e Gullikson, Kevin; et al. (2016), "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars", The Astronomical Journal , 152 (2): 40, arXiv :1604.06456 , Bibcode :2016AJ....152...40G , doi :10.3847/0004-6256/152/2/40 , S2CID 119179065 .
^ a b c Cotten, Tara H.; Song, Inseok (July 2016), "A Comprehensive Census of Nearby Infrared Excess Stars", The Astrophysical Journal Supplement Series , 225 (1): 24, arXiv :1606.01134 , Bibcode :2016ApJS..225...15C , doi :10.3847/0067-0049/225/1/15 , S2CID 118438871 , 15.
^ a b c 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 Uesugi, Akira; Fukuda, Ichiro (1970), "Catalogue of rotational velocities of the stars", Contributions from the Institute of Astrophysics and Kwasan Observatory , University of Kyoto, Bibcode :1970crvs.book.....U .
^ "tet Nor" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2017-08-12 .{{cite web }}
: CS1 maint: postscript (link )
^ Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters , 38 (11): 694– 706, arXiv :1606.09028 , Bibcode :2012AstL...38..694G , doi :10.1134/S1063773712110035 , S2CID 119108982 .
^ Chini, R.; et al. (2012), "A spectroscopic survey on the multiplicity of high-mass stars", Monthly Notices of the Royal Astronomical Society , 424 (3): 1925– 1929, arXiv :1205.5238 , Bibcode :2012MNRAS.424.1925C , doi :10.1111/j.1365-2966.2012.21317.x , S2CID 119120749 .
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