Theta Pegasi
θ Pegasi, Latinized as Theta Pegasi, is a single star in the equatorial constellation of Pegasus, lying about 7.5 degrees southwest of Enif. It has the traditional name Biham, and the Flamsteed designation 26 Pegasi. This object is visible to the naked eye as a white-hued point of light with an apparent visual magnitude of +3.52. The system is located 92 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −8 km/s.
This object an A-type main-sequence star with a stellar classification of A2V. It is 448 million years old with a high rate of spin, showing a projected rotational velocity of 136 km/s. This star has 2.14 times the mass of the Sun and 2.6 times the Sun's radius. It is radiating 25 times the luminosity of the Sun from its outer envelope at an effective temperature of 7,951 K. The star appears to display a slight infrared excess.Nomenclature
θ Pegasi is the star's Bayer designation.
It bore the traditional name Biham or Baham from the Arabic phrase s'ad al Biham "Lucky Stars of the Young Beasts". In 2016, the International Astronomical Union organized a Working Group on Star Names to catalogue and standardize proper names for stars. The WGSN approved the name Biham for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.
In Chinese, 危宿, meaning Rooftop, refers to an asterism consisting of Theta Pegasi, Alpha Aquarii and Epsilon Pegasi. Consequently, the Chinese name for Theta Pegasi itself is 危宿二
