Tau Orionis

τ Orionis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Orion
Right ascension 05h 17m 36.38856s[1]
Declination −06° 50′ 39.8702″[1]
Apparent magnitude (V) 3.58[2]
Characteristics
Spectral type B5 III[3]
U−B color index −0.47[2]
B−V color index −0.11[2]
Astrometry
Radial velocity (Rv)+20.1[4] km/s
Proper motion (μ) RA: −17.61[1] mas/yr
Dec.: −9.24[1] mas/yr
Parallax (π)6.60 ± 0.15 mas[1]
Distance490 ± 10 ly
(152 ± 3 pc)
Details
Mass6.2±0.1[5] M☉
Radius5.4[6] R☉
Luminosity933[7] L☉
Temperature10,829[7] K
Rotational velocity (v sin i)40[8] km/s
Age63.1±15.6[5] Myr
Other designations
τ Ori, 20 Orionis, BD−07° 1028, HD 34503, HIP 24674, HR 1735, SAO 131952.[9]
Database references
SIMBADdata

Tau Orionis (τ Ori, τ Orionis) is a solitary[10] star in the constellation Orion. If an imaginary line is drawn north-west between the stars Rigel and Mintaka, Tau Orionis can be found roughly one-sixth of the way to Mintaka. It is visible to the naked eye with an apparent visual magnitude of 3.58.[2] Based upon an annual parallax shift of 6.6 mas,[1] it is located around 490 light years from the Sun.

This is a B-type giant star with a stellar classification of B5III5 III.[3] It has around 5.4[6] times the radius of the Sun and 6.2[5] times the Sun's mass. The star shines with 933[7] times the solar luminosity from its outer atmosphere at an effective temperature of 10,829[7] K. it is around 63[5] million years old, with a peculiar velocity through space of 16.9 km/s.[5]

Tau Orionis has three visual companions: magnitude 11.0 component B at an angular separation of 33.30″ along a position angle of 251°; magnitude 10.9 component C lying some 3.80″ from component B; and magnitude 10.9 component D at 36.0″ from τ Ori along a position angle of 51°, all as of 2011.[11]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Crawford1971 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference abt1985 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Wilson1953 was invoked but never defined (see the help page).
  5. ^ a b c d e Cite error: The named reference tetzlaff2011 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference PasinettiFracassini2001 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Abt2002 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference WDSC2014 was invoked but never defined (see the help page).