Omicron1 Orionis
Binary star system in the constellation Orion From Wikipedia, the free encyclopedia
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]
| 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] |
| Distance | approx. 650 ly (approx. 200 pc) |
| Details | |
| Mass | 0.9[6] M☉ |
| Radius | 214±29[6] R☉ |
| Luminosity | 4,046[7] L☉ |
| Surface gravity (log g) | 0.76±0.29[8] cgs |
| Temperature | 3,465±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 | |
| SIMBAD | data |
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] The variability of the brightness of ο1 Orionis was announced by Joel Stebbins and Charles Morse Huffer in 1928, based on observations made at Washburn Observatory.[11]It is a semiregular variable[12] that is pulsating with periods of 30.8 and 70.7 days, each with nearly identical amplitudes of 0.05 in magnitude.[13] 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]
References
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