12 Pegasi
K-type supergiant star in the constellation of Pegasus
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12 Pegasi is a K-type supergiant star in the northern constellation of Pegasus. It is faintly visible to the naked eye with an apparent visual magnitude of +5.3.[2] Based on parallax measurements, it is located at a distance of approximately 1,380 light-years (420 pc) from the Earth. The star is drifting closer with a line of sight velocity component of â10.1 km/s.[5]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 21h 46m 04.364s[1] |
| Declination | +22° 56â² 55.96â³[1] |
| Apparent magnitude (V) | +5.266[2] |
| Characteristics | |
| Evolutionary stage | Supergiant |
| Spectral type | K0IbHdel0.5[3] |
| UâB color index | +1.33[4] |
| BâV color index | +1.41[4] |
| Astrometry | |
| Radial velocity (Rv) | â10.14±0.20[5] km/s |
| Proper motion (μ) | RA: 8.299[1] mas/yr[1] Dec.: â2.478 mas/yr[1] |
| Parallax (Ï) | 2.3673±0.1279 mas[1] |
| Distance | 1,380 ± 70 ly (420 ± 20 pc) |
| Absolute magnitude (MV) | â4.03[4] |
| Details | |
| Mass | 6.3[6] Mâ |
| Radius | 81[7] Râ |
| Luminosity | 1,722â1,820[7] Lâ |
| Surface gravity (log g) | 1.11[8] cgs |
| Temperature | 4,185[7] K |
| Metallicity [Fe/H] | +0.03[8] dex |
| Rotational velocity (v sin i) | 19.5[9] km/s |
| Age | 19.8[6] Myr |
| Other designations | |
| 12 Peg, BD+22°4472, FK5 3739, GC 30479, HD 207089, HIP 107472, HR 8321, SAO 89962, PPM 113549[10] | |
| Database references | |
| SIMBAD | data |
This evolved star has a spectral type of K0Ib Hdel0.5,[11] which indicates that it is a less luminous K-type supergiant with strong H-δ Balmer lines. It is an estimated 20[6] million years old and is spinning with a projected rotational velocity of 19.5 km/s.[9] With 6.3 times the mass of the Sun,[6] it has expanded to 81 times the radius of the Sun. The star is radiating 1,722â1,820[7] times the luminosity of the Sun from its photosphere at an effective temperature of 4,185 K.[7]