Omicron1 Orionis

For other stars with this Bayer designation, see ο Orionis.
ο1 Orionis
Location of ο1 Orionis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Orion
Right ascension 04h 52m 31.96357s[1]
Declination +14° 15′ 02.3215″[1]
Apparent magnitude (V) 4.65 - 4.88[2]
Characteristics
Spectral type M3S III[3]
U−B color index +2.03[4]
B−V color index +1.74[4]
Variable type SRb[2]
Astrometry
Radial velocity (Rv)−8.40±0.23[5] km/s
Proper motion (μ) RA: −0.05[1] mas/yr
Dec.: −54.81[1] mas/yr
Parallax (π)5.01 ± 0.71 mas[1]
Distanceapprox. 650 ly
(approx. 200 pc)
Details
Mass0.9[6] M☉
Radius214±29[6] R☉
Luminosity4,046[7] L☉
Surface gravity (log g)0.76±0.29[8] cgs
Temperature3,465±27[8] K
Metallicity [Fe/H]−0.03±0.12[8] dex
Other designations
ο1 Ori, 4 Orionis, BD+14 777, FK5 1136, HD 30959, HIP 22667, HR 1556, SAO 94176
Database references
SIMBADdata

Omicron1 Orionis (ο1 Ori) is a binary star[9] in the northeastern corner of the constellation Orion. It is visible to the naked eye with an apparent visual magnitude of 4.7.[4] Based upon an annual parallax shift of 5.01±0.71 mas, it is located approximately 650 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an interstellar absorption factor of 0.27 due to intervening dust.[5]

A light curve for Omicron1 Orionis, plotted from Hipparcos data[10]

The two components of this system have an orbital period of greater than 1,900 days (5.2 years).[9] The primary component is an evolved red giant with the stellar classification of M3S III. This is an S-type star on the asymptotic giant branch.[3] It is a semiregular variable[11] that is pulsating with periods of 30.8 and 70.7 days, each with nearly identical amplitudes of 0.05 in magnitude.[12] The star has an estimated 90% of the mass of the Sun but has expanded to 214 times the Sun's radius.[6] It shines with 4,046[7] times the solar luminosity from its outer atmosphere at an effective temperature of 3,465 K.[8]

  1. ^ a b c d e Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference gcvs was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Cox2012 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Famaey2005 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference cruzalebes2013 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  8. ^ a b c d Cite error: The named reference Vauglin2011 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Udry1998 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference CDS was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference glass2007 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Tabur2009 was invoked but never defined (see the help page).