Omicron2 Orionis

For other stars with this Bayer designation, see ο Orionis.
ο2 Orionis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Orion
Right ascension 04h 56m 22.27612s[1]
Declination +13° 30′ 52.0932″[1]
Apparent magnitude (V) 4.06[2]
Characteristics
Spectral type K2 IIIb[3]
U−B color index +1.14[2]
B−V color index +1.17[2]
Astrometry
Radial velocity (Rv)2.54±0.15[4] km/s
Proper motion (μ) RA: −74.88[1] mas/yr
Dec.: −44.33[1] mas/yr
Parallax (π)17.54 ± 0.21 mas[1]
Distance186 ± 2 ly
(57.0 ± 0.7 pc)
Absolute magnitude (MV)0.501[5]
Details[4]
Radius15 R☉
Luminosity79 L☉
Surface gravity (log g)2.4 cgs
Temperature4,498 K
Metallicity [Fe/H]−0.26 dex
Rotational velocity (v sin i)0.0 km/s
Age5.42±2.38[5] Gyr
Other designations
ο2 Ori, 9 Orionis, BD+13° 740, HD 31421, HIP 22957, HR 1580, SAO 94218.[6]
Database references
SIMBADdata

Omicron2 Orionis (ο2 Ori) is a solitary[7] star in the constellation Orion. It has an apparent visual magnitude of 4.06,[2] which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 17.54 mas, it is around 186 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an interstellar absorption factor of 0.09 due to intervening dust.[8]

This is a red clump[5] giant star with a stellar classification of K2 IIIb.[3] It is around 5.4[5] billion years old with a projected rotational velocity that is too small to be measured. The star has expanded to about 15 times the radius of the Sun and shines with 79 times the solar luminosity from its outer atmosphere at an effective temperature of 4,498 K.[4] Omicron2 Orionis is most likely a member of the Milky Way's thin disk population.[5]

  1. ^ a b c d e 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 Mermilliod1986 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Luck2015 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Massarotti2008 was invoked but never defined (see the help page).
  5. ^ a b c d e Cite error: The named reference Soubiran2008 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Famaey2005 was invoked but never defined (see the help page).