Nu Cephei (ν Cephei) is a class A2, fourth-magnitude

supergiant Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram with absolute visual magnitudes between about −3 and −8. The temperature range of supergiant stars spa ...

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Cepheus. It is a white pulsating α Cygni variable star located about 4,700

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s from Earth. ν Cephei is a member of the Cepheus OB2

stellar association A stellar association is a very loose star cluster, looser than both open clusters and globular clusters. Stellar associations will normally contain from 10 to 100 or more stars. The stars share a common origin, but have become gravitationally u ...

, which includes stars such as μ Cephei and

VV Cephei VV Cephei, also known as HD 208816, is an eclipsing binary star system located in the constellation Cepheus, approximately 5,000 light years from Earth. It is both a B star and shell star. VV Cephei is an eclipsing binary with the ...

. It began life as an approximately star around eight million years ago. It has now exhausted its core hydrogen and expanded and cooled into a supergiant. Elemental abundance analyses indicate that it has not yet spent time as a red supergiant, which would have brought about convection of fusion products to the surface in a

Dredge-up A dredge-up is any one of several stages in the evolution of some stars. By definition, during a ''dredge-up'', a convection zone extends all the way from the star's surface down to the layers of material that have undergone fusion. Consequently, th ...

. ν Cephei is currently about 15 times as massive as the sun, 190 times as large, and 100,000 times as luminous. Its large size and luminosity cause it to be somewhat unstable and produce irregular pulsations. This is a common feature of class A and B supergiants, which are grouped as α Cygni variable stars. The brightness changes by at most a tenth of a magnitude.

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{{DEFAULTSORT:Nu Cephei Cephei, Nu 207260 A-type supergiants Cepheus (constellation) Alpha Cygni variables Cephei, 10 107418 8335 Durchmusterung objects