Phi2 Orionis
Star in the constellation Orion
From Wikipedia, the free encyclopedia
Phi2 Orionis is a star in the constellation Orion, where it forms a small triangle on the celestial sphere with the nearby Meissa and Phi1 Orionis.[8] This star is visible to the naked eye with an apparent visual magnitude of 4.081.[2] Based upon an annual parallax shift of 28.67 mas,[6] it is located around 114 light-years from the Sun.
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 36m 54.389s[1] |
| Declination | +09° 17′ 26.42″[1] |
| Apparent magnitude (V) | 4.081[2] |
| Characteristics | |
| Evolutionary stage | Yellow giant |
| Spectral type | G8 III-IV[3] |
| U−B color index | +0.618[2] |
| B−V color index | +0.966[2] |
| Astrometry | |
| Radial velocity (Rv) | 99.03±0.18[1] km/s |
| Proper motion (μ) | RA: +98.301 mas/yr[1] Dec.: −305.022 mas/yr[1] |
| Parallax (π) | 28.6722±0.1859 mas[1] |
| Distance | 113.8 ± 0.7 ly (34.9 ± 0.2 pc)[1] |
| Absolute magnitude (MV) | +1.33±0.07[4] |
| Details[5] | |
| Mass | 1.07±0.04 M☉ |
| Radius | 8.22±0.07[6] R☉ |
| Luminosity | 29.8±0.4[6] L☉ |
| Surface gravity (log g) | 3.00±0.02 cgs |
| Temperature | 4,703±11[6] K |
| Metallicity [Fe/H] | −0.56±0.02 dex |
| Rotational velocity (v sin i) | 1.91±0.53 km/s |
| Age | 6.91±1.04 Gyr |
| Other designations | |
| φ2 Ori, 40 Orionis, BD+09°898, HD 37160, HIP 26366, HR 1907, SAO 112958[7] | |
| Database references | |
| SIMBAD | data |
This is an evolved G-type star of stellar classification G8 III-IV,[3] which means that it is in an evolutionary stage between a subgiant (IV) and a giant star (III). It is estimated to be 6.9 billion years old, has 1.07 times the mass of the Sun,[5] but has expanded to 8 times the Sun's radius. The star shines with 30 times the solar luminosity from its outer atmosphere at an effective temperature of 4,700 K.[6]