Observation data Epoch J2000 Equinox J2000 |
|
---|---|
Constellation | Pegasus |
Right ascension | 00h 13m 14.15123s |
Declination | +15° 11′ 00.9368″ |
Apparent magnitude (V) | +2.84 |
Characteristics | |
Spectral type | B2 IV |
U−B color index | –0.85 |
B−V color index | –0.23 |
Variable type | β Cep |
Astrometry | |
Radial velocity (Rv) | +4.1 km/s |
Proper motion (μ) |
RA: +1.98 mas/yr Dec.: –9.28 mas/yr |
Parallax (π) | 8.33 ± 0.53mas |
Distance | 390 ± 20 ly (120 ± 8 pc) |
Details | |
Mass | 8.9 ± 0.1 M☉ |
Radius | 4.80 ± 0.39 R☉ |
Luminosity | 5,840 L☉ |
Surface gravity (log g) | 3.98 ± 0.06 cgs |
Temperature | 21,179 ± 237 K |
Metallicity [Fe/H] | –0.34 dex |
Rotational velocity (v sin i) | 0 km/s |
Age | 18.7 ± 3.2 Myr |
Other designations | |
Gamma Pegasi (γ Pegasi, abbreviated Gamma Peg or γ Peg), also named Algenib, is a star in the constellation of Pegasus, located at the southwest corner of the asterism known as the Great Square. The average apparent visual magnitude of +2.84 puts this at fourth place among the brightest stars in the constellation. The distance to this star has been measured using the parallax technique, yielding a value of roughly 390 light-years (120 parsecs) with a margin of error of 5%.
Gamma Pegasi is the star's Bayer designation. Although it also had the traditional name Algenib, this name was also used for Alpha Persei. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included Algenib for this star (Alpha Persei was given the name Mirfak).
The asterism of γ Pegasi and α Andromedae, in Hindu astronomy, is called Uttara Bhādrapadā (उत्तरभाद्रपदा) or Uttṛṭṭāti. It is the 26th nakshatra. In Chinese, 壁宿 (Bìxiù), meaning Wall (asterism) refers to an asterism consisting of γ Pegasi and α Andromedae . Consequently, γ Pegasi itself is known as 壁宿一 (Bìxiù yī, English: the First Star of Wall.)