AO Cassiopeiae, also known as Pearce's Star, is a

binary system A binary system is a system of two astronomical bodies of the same kind that are comparable in size. Definitions vary, but typically require the center of mass to be located outside of either object. (See animated examples.) The most common ki ...

composed of an O8 main sequence star and an O9.2 bright giant that respectively weigh anywhere between 20.30 and 57.75 times and 14.8 and 31.73 times the mass of the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

The AO Cas system is an

eclipsing binary A binary star or binary star system is a Star system, system of two stars that are gravity, gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved ...

with a period of roughly 3.5 days, with the apparent magnitude ranging between 6.07 and 6.24. Stars of this brightness are generally just visible to the unaided eye in dark skies in semirural locations. The component stars are so close to each other they are ellipsoidal (egg-shaped). AO Cas is considered a contact binary, with both stars at or near their

Roche lobe In astronomy, the Roche lobe is the region around a star in a binary system within which orbiting material is gravitationally bound to that star. It is an approximately teardrop-shaped region bounded by a critical gravitational equipotential, ...

References

External links

* http://jumk.de/astronomie/special-stars/ao-cassiopeiae.shtml {{Stars of Cassiopeia Eclipsing binaries Cassiopeia (constellation) 001337 Cassiopeiae, AO 0065 O-type bright giants O-type main-sequence stars 001415 BD+50 0046 Emission-line stars