Theta Arietis

θ Arietis
Location of θ Arietis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aries
Right ascension 02h 18m 07.53022s[1]
Declination +19° 54′ 04.1717″[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]
Variable type Constant[5]
Astrometry
Radial velocity (Rv)+6.0[2] km/s
Proper motion (μ) RA: −7.491[1] mas/yr
Dec.: −3.978[1] mas/yr
Parallax (π)7.6084 ± 0.1763 mas[1]
Distance429 ± 10 ly
(131 ± 3 pc)
Absolute magnitude (MV)−0.10[6]
Details
A
Mass2.10+0.37
−0.31 M☉[7]
2.94±0.06[8] M☉
Radius1.9–2.5[9] R☉
Luminosity106[6] L☉
Surface gravity (log g)4.00±0.25[7] cgs
Temperature9,500±1,000[7] K
Rotational velocity (v sin i)186[10] km/s
Age107+286
−93[7] Myr
B
Mass1.0+0.02
−0.04[7] M☉
Temperature5,578±109[7] K
Metallicity [Fe/H]0.0[7] dex
Rotational velocity (v sin i)5[7] km/s
Other designations
θ Ari, 22 Arietis, BD+19 340, FK5 81, HD 14191, HIP 10732, HR 669, SAO 92877[11]
Database references
SIMBADdata

Theta Arietis, Latinised from θ Arietis, is the Bayer designation for a binary star[7] system 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 7.61 mas,[1] the distance to this star is an estimated 429 light-years (132 parsecs) with a 10-light-year margin of error. It is drifting further away with a radial velocity of +6 km/s.[2]

The primary, component A, 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.[10] This is causing the "nebulous" appearance of the 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.[5]

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]

  1. ^ a b c d e f Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference scfs was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference aj74_375 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference aa19_229 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Neiner_et_al_2005 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b c d e f g h i j Cite error: The named reference Gullikson_et_al_2016 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Zorec_Royer_2012 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference aaa367_521 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference aaa463_2_671 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).