Pi2 Orionis
Star in the constellation Orion
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Pi2 Orionis (π2 Ori, π2 Orionis) is the Bayer designation for a solitary star in the equatorial constellation of Orion. Although the Bright Star Catalogue lists this as a spectroscopic binary star system,[10] this does not appear to be the case.[11] It is visible to the naked eye with an apparent visual magnitude of 4.35.[2] Based upon an annual parallax shift of 14.53 mas,[1] it is located roughly 224 light-years away from the Sun.
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Orion |
| Right ascension | 04h 50m 36.72298s[1] |
| Declination | +08° 54′ 00.6493″[1] |
| Apparent magnitude (V) | 4.35[2] |
| Characteristics | |
| Spectral type | A1 Vn[3] |
| U−B color index | +0.03[2] |
| B−V color index | +0.01[2] |
| Astrometry | |
| Radial velocity (Rv) | 24[4] km/s |
| Proper motion (μ) | RA: +1.41[1] mas/yr Dec.: −29.91[1] mas/yr |
| Parallax (π) | 14.53±0.38 mas[1] |
| Distance | 224 ± 6 ly (69 ± 2 pc) |
| Absolute magnitude (MV) | 0.48[5] |
| Details | |
| Radius | 2.7[6] R☉ |
| Luminosity | 70[7] L☉ |
| Surface gravity (log g) | 4.00±0.05[8] cgs |
| Temperature | 9,457±128[8] K |
| Metallicity [Fe/H] | −0.20±0.10[8] dex |
| Rotational velocity (v sin i) | 261.4±13.5[5] km/s |
| Other designations | |
| π2 Ori, 2 Orionis, BD+08°777, HD 30739, HIP 22509, HR 1544, SAO 112124[9] | |
| Database references | |
| SIMBAD | data |
This is an A-type main-sequence star with a stellar classification of A1 Vn,[3] where the 'n' indicates broad absorption lines due to rotation. It is spinning rapidly with a projected rotational velocity of 261.4 km/s.[5] This is giving the star an oblate shape with an equatorial bulge that is 13% larger than the polar radius.[12] It is shining with 70[7] times the solar luminosity from its outer atmosphere at an effective temperature of 9,457 K.[8]