9 Pegasi (9 Peg) is a supergiant star in the constellation Pegasus. Its

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's ...

is 4.35. 9 Pegasi is defined and used as an MK standard star for the spectral type G5 Ib. It is a

yellow supergiant A yellow supergiant (YSG) is a star, generally of spectral type F or G, having a supergiant luminosity class (e.g. Ia or Ib). They are stars that have evolved away from the main sequence, expanding and becoming more luminous. Yellow supergiants ...

nearly two thousand times more luminous than the sun and sixty times larger. It has been reported to be slightly variable and is listed in the

New Catalogue of Suspected Variable Stars The ''New Catalogue of Suspected Variable Stars'' (NSV) is a star catalogue A star catalogue is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different ...

with a magnitude range of 4.20 to 4.35. 9 Pegasi does not have a Bayer designation although it is brighter than several stars in Pegasus that do such as τ, φ, and σ Pegasi. It is the 9th star numbered by Flamsteed in order of right ascension. In the 1795 French-language Fortin-Flamsteed edition of the

Atlas Coelestis The ''Atlas Coelestis'' is a star atlas published posthumously in 1729, based on observations made by the First Astronomer Royal, John Flamsteed. The ''Atlas'' – the largest that ever had been published and the first comprehensive telescopic ...

, 9 Pegasi is labelled with the letter "g".

References

{{DEFAULTSORT:9 Pegasi Pegasus (constellation) G-type supergiants Suspected variables Pegasi, 09 8313 206859 107348 BD+16 4582