Alpha Pegasi
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 23h 04m 45.65345s |
| Declination | +15° 12′ 18.9617″ |
| Apparent magnitude (V) | 2.48 |
| Characteristics | |
| Evolutionary stage | Giant star or main sequence star |
| Spectral type | B9V, B9.5III, B9III A0 IV |
| U−B color index | –0.06 |
| B−V color index | –0.04 |
| Variable type | suspected |
| Astrometry | |
| Radial velocity (Rv) | –2.2 km/s |
| Proper motion (μ) | RA: 60.40 ± 0.17 mas/yr Dec.: -41.30 ± 0.16 mas/yr |
| Parallax (π) | 24.46±0.19 mas |
| Distance | 133 ± 1 ly (40.9 ± 0.3 pc) |
| Absolute magnitude (MV) | –0.718 |
| Details | |
| Mass | 3.5 M☉ |
| Radius | 4.62±0.29 R☉ |
| Luminosity | 165 L☉ |
| Surface gravity (log g) | 3.98±0.25 cgs |
| Temperature | 10,100±100 K |
| Metallicity [Fe/H] | −0.28 dex |
| Rotational velocity (v sin i) | 130 km/s |
| Age | 200 Myr |
| Other designations | |
| Markab, Marchab, 54 Pegasi, HR 8781, BD+14°4926, HD 218045, SAO 108378, FK5 871, HIP 113963 | |
| Database references | |
| SIMBAD | data |
Alpha Pegasi (α Pegasi, abbreviated Alpha Peg, α Peg), formally named Markab /ˈmɑːrkæb/, is the third-brightest star in the constellation of Pegasus and one of the four stars in the asterism known as the Great Square of Pegasus.