Pi1 Pegasi
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 22h 09m 13.61893s |
| Declination | +33° 10′ 20.4778″ |
| Apparent magnitude (V) | +5.58 |
| Characteristics | |
| Spectral type | G8IIIb |
| B−V color index | +0.985±0.003 |
| Astrometry | |
| Radial velocity (Rv) | +5.1±0.9 km/s |
| Proper motion (μ) | RA: −48.117 mas/yr Dec.: −73.408 mas/yr |
| Parallax (π) | 10.2111±0.1137 mas |
| Distance | 319 ± 4 ly (98 ± 1 pc) |
| Absolute magnitude (MV) | 0.84 |
| Details | |
| Radius | 11.00+0.51 −0.83 R☉ |
| Luminosity | 62.8±0.8 L☉ |
| Surface gravity (log g) | 2.7 cgs |
| Temperature | 4,898+196 −110 K |
| Metallicity [Fe/H] | −0.22 dex |
| Rotational velocity (v sin i) | 4 km/s |
| Other designations | |
| π1 Peg, 27 Pegasi, BD+32°4349, HD 210354, HIP 109352, HR 8449, SAO 72064 | |
| Database references | |
| SIMBAD | data |
Pi1 Pegasi, Latinized from π1 Pegasi, is a star in the constellation Pegasus. Based upon changes to the proper motion of the visible component, this is a probable astrometric binary. It has a yellow hue and is dimply visible to the naked eye with a combined apparent visual magnitude of +5.58. The system is located approximately 319 light years distant from the Sun based on parallax, and is drifting further away with a radial velocity of +5 km/s.
The visible component is an aging giant star with a stellar classification of G8IIIb. With the supply of hydrogen exhausted at its core, the star has cooled and expanded to 11 times the Sun's radius. It is radiating 63 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,898 K.