Beta Pegasi is a star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

 in the constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 Pegasus

Pegasus (constellation)

Pegasus is a constellation in the northern sky, named after the winged horse Pegasus in Greek mythology. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.-Stars:...

. Its traditional name is Scheat, a name that has also been used for Delta Aquarii

Delta Aquarii

Delta Aquarii is the third-brightest star in the constellation Aquarius. It has the traditional name Skat, which has also been used for Beta Pegasi....

.

Beta Pegasi is unusual among bright stars in having a relatively cool surface temperature (3700 kelvin

Kelvin

The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...

s) compared to stars like the Sun

Sun

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

. It is a red giant

Red giant

A red giant is a luminous giant star of low or intermediate mass in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius immense and the surface temperature low, somewhere from 5,000 K and lower...

 some 95 times as large, and has a total luminosity

Luminosity

Luminosity is a measurement of brightness.-In photometry and color imaging:In photometry, luminosity is sometimes incorrectly used to refer to luminance, which is the density of luminous intensity in a given direction. The SI unit for luminance is candela per square metre.The luminosity function...

 of 1500 times that of the Sun.

Beta Pegasi is a slow irregular variable

Slow irregular variable

A slow irregular variable is a variable star that exhibit no or very poorly defined periodicity in their slowly changing light emissions. Most of them are late spectral types K and M, S stars or carbon stars...

 star of the type LB. Its brightness varies from magnitude

Apparent magnitude

The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...

+2.31 to +2.74.