Theta Arietis

Theta Arietis
Diagram showing star positions and boundaries of the Aries constellation and its surroundings


Location of θ Arietis (circled)

Observation data
Epoch J2000      Equinox J2000
Constellation Aries
Right ascension 02h 18m 07.53838s[1]
Declination +19° 54′ 04.1862″[1]
Apparent magnitude (V) 5.58[2]
Characteristics
Spectral type A1 Vn[3]
U−B color index +0.02[4]
B−V color index +0.01[4]
Astrometry
Radial velocity (Rv)+6.0[2] km/s
Proper motion (μ) RA: –13.19[1] mas/yr
Dec.: +0.72[1] mas/yr
Parallax (π)7.29 ± 0.29[1] mas
Distance450 ± 20 ly
(137 ± 5 pc)
Details
Radius1.9–2.5[5] R☉
Rotational velocity (v sin i)186[6] km/s
Other designations
22 Arietis, BD+19 340, FK5 81, HD 14191, HIP 10732, HR 669, SAO 92877.[7]

Theta Arietis (θ Ari, θ Arietis) is the Bayer designation ]for a star in the northern constellation of Aries. It is faintly visible to the naked eye with an apparent visual magnitude of 5.58.[2] With an annual parallax shift of 7.29 mas,[1] the distance to this star is an estimated 450 light-years (140 parsecs) with a 20 light-year margin of error.

This is a white-hued, A-type main sequence star with a stellar classification of A1 Vn.[3] It is spinning at a rapid pace as shown by the projected rotational velocity of 186 km/s.[6] This is causing the "nebulous" appearance of the absorption lines indicated by the 'n' suffix in the classification.

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (November 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.
  2. ↑ 2.0 2.1 2.2 Wielen, R. et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions (35), Astronomisches Rechen-Institut Heidelberg, Bibcode:1999VeARI..35....1W.
  3. ↑ 3.0 3.1 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.
  4. ↑ 4.0 4.1 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.
  5. ↑ 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: 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  6. ↑ 6.0 6.1 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.
  7. ↑ "tet Ari -- Star", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), retrieved 2012-08-06.

External links