Pi2 Pegasi
Single star in the constellation Pegasus
From Wikipedia, the free encyclopedia
π2 Pegasi, Latinized as Pi2 Pegasi, is a single[8] star in the northern constellation Pegasus. It is yellow-white in hue and visible to the naked eye as a faint point of light with an apparent visual magnitude of +4.28.[2] The distance to this object is approximately 263 light years based on parallax,[1] and it is drifting further away with a radial velocity of +5 km/s.[2] This star is an outlying member of the Ursa Major Moving Group.[9]
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 22h 09m 59.24371s[1] |
| Declination | +33° 10′ 41.5976″ [1] |
| Apparent magnitude (V) | +4.28[2] |
| Characteristics | |
| Spectral type | F5 III[3] |
| B−V color index | 0.471±0.012[2] |
| Astrometry | |
| Radial velocity (Rv) | +5.1±0.9[2] km/s |
| Proper motion (μ) | RA: −12.87±0.12[1] mas/yr Dec.: −18.95±0.16[1] mas/yr |
| Parallax (π) | 12.40±0.17 mas[1] |
| Distance | 263 ± 4 ly (81 ± 1 pc) |
| Absolute magnitude (MV) | 0.21[4] |
| Details | |
| Mass | 2.48[5] M☉ |
| Radius | 8.5±0.8[6] R☉ |
| Luminosity | 102.9±2.6[6] L☉ |
| Temperature | 6,300+298 −263[6] K |
| Rotational velocity (v sin i) | 139.7[4] km/s |
| Age | 530[5] Myr |
| Other designations | |
| π2 Peg, 29 Pegasi, BD+32°4352, FK5 835, HD 210459, HIP 109410, HR 8454, SAO 72077[7] | |
| Database references | |
| SIMBAD | data |
This object has a stellar classification of F5 III,[3] matching an aging giant star that has exhausted the supply of hydrogen at its core then cooled and expanded off the main sequence. At present it has 8.5[6] times the radius of the Sun. The star is 530[5] million years old with 2.48[5] times the Sun's mass. It shows a high rotation rate considering its evolutionary status, with a projected rotational velocity of 140 km/s.[4] The star has been noted as a possible variable shell star.[10] Pi2 Pegasi is radiating 103 times the Sun's luminosity from its swollen photosphere at an effective temperature of 6,300 K.[6]