Binary star system in the constellation Aries
θ Arietis
Location of θ Arietis (circled)
Observation dataEpoch J2000 Equinox J2000
Constellation
Aries [ 1]
Right ascension 02h 18m 07.531s [ 2]
Declination
+19° 54′ 04.17″[ 2]
Apparent magnitude (V)5.58[ 3]
Characteristics
Spectral type
A1 Vn[ 4]
U−B color index
+0.02[ 5]
B−V color index
+0.01[ 5]
Variable type
Constant[ 6]
Astrometry Radial velocity (Rv )+11.95± 0.78[ 2] km/s Proper motion (μ) RA: −7.832 mas /yr [ 2] Dec.: −3.654 mas /yr [ 2] Parallax (π)7.2220± 0.1043 mas [ 2] Distance 452 ± 7 ly pc ) Absolute magnitude (MV )−0.10[ 1] Details A Mass +0.37 M ☉ [ 7] ± 0.06[ 8] M ☉ Radius 1.9–2.5[ 9] R ☉ Luminosity 106[ 1] L ☉ Surface gravity (log g )± 0.25[ 7] cgs Temperature ± 1,000[ 7] K Rotational velocity (v sin i )186[ 10] Age +286 [ 7] Myr B Mass +0.02 [ 7] M ☉ Temperature ± 109[ 7] K Metallicity [Fe/H] 0.0[ 7] dex Rotational velocity (v sin i )5[ 7] Other designations θ Ari , 22 Arietis , BD +19 340FK5 81HD 14191HIP 10732HR 669SAO 92877[ 11] Database references SIMBAD data
Theta Arietis , is a binary star [ 7] northern constellation of Aries . Its name is a Bayer designation that is Latinised from θ Arietis, and abbreviated Theta Ari or θ Ari. This star is faintly visible to the naked eye with an apparent visual magnitude of 5.58.[ 3] parallax shift of mas [ 2] star is an estimated 452 light-years (139 parsecs ) with a 7-light-year margin of error . It is drifting further away from the Sun with a radial velocity of +12 km/s.[ 2]
The primary, component A, is a white-hued, A-type main-sequence star with a stellar classification of A1 Vn.[ 4] projected rotational velocity of 186 km/s.[ 10] absorption lines indicated by the 'n' suffix in the classification. In 2005, C. Neiner and associates classified this as a Be star because is displays emission features in the hydrogen Balmer lines .[ 6]
In 2016, a solar-mass companion was reported in close orbit around this star, based on observations using adaptive optics with the Gemini North Telescope .[ 7]
^ a b c 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 . XHIP record for this object at VizieR .^ a b c d e f g Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties" . Astronomy and Astrophysics . 674 : A1. arXiv :2208.00211 Bibcode :2023A&A...674A...1G . doi :10.1051/0004-6361/202243940 S2CID 244398875 . Gaia DR3 record for this source at VizieR .^ a b Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg , 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode :1999VeARI..35....1W . ^ a b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal , 74 : 375– 406, Bibcode :1969AJ.....74..375C , doi :10.1086/110819 . ^ a b Rybka, E. (1969), "The corrected magnitudes and colours of 278 stars near S.A. 1-139 in the UBV system", Acta Astronomica , 19 : 229, Bibcode :1969AcA....19..229R . ^ a b Neiner, C.; et al. (February 2005), "The Identification of New Be Stars in GAUDI", The Astrophysical Journal Supplement Series , 156 (2): 237– 243, Bibcode :2005ApJS..156..237N , doi :10.1086/426670 S2CID 123143757 . ^ a b c d e f g h i j Gullikson, Kevin; et al. (August 2016), "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars", The Astronomical Journal , 152 (2): 13, arXiv :1604.06456 Bibcode :2016AJ....152...40G , doi :10.3847/0004-6256/152/2/40 S2CID 119179065 , 40. ^ Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics , 537 : A120, arXiv :1201.2052 Bibcode :2012A&A...537A.120Z , doi :10.1051/0004-6361/201117691 , S2CID 55586789 . ^ Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics , 367 (2): 521– 524, arXiv :astro-ph/0012289 Bibcode :2001A&A...367..521P , doi :10.1051/0004-6361:20000451 , S2CID 425754 . ^ a b Royer, F.; Zorec, J.; Gómez, A. E. (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 . ^ "* tet Ari" , SIMBAD Centre de données astronomiques de Strasbourg , retrieved 2012-08-06 . 
