Other oblate stars that are well-known examples of this are Vega, Altair, Achernar, Regulus, Alderamin and Rasalhague. The phenomenon is known as gravity darkening. The temperature at the poles is about 1,000 K higher than at the equator. Because the poles are closer to the centre of mass, they also have a higher temperature and luminosity than the equatorial region. As a result of its fast rotation, the star has an oblate spheroid shape and its equatorial radius is 24% larger than its polar radius. With a projected rotational velocity of 71 km/s, it spins at about 92% of its critical rate. Among the confirmed ones, only Altair is brighter than Caph.Ĭaph is a very fast spinner. The bright Vega in Lyra and Denebola in Leo are also suspected Delta Scuti variables. Other stars of this type include Altair in the constellation Aquila, Seginus in Boötes, Polaris Australis in Octans, and Epsilon Cephei in Cepheus. Caph’s brightness varies from magnitude 2.25 to 2.31 every 2.5 hours. This means that some parts of the star’s surface move inwards while others move outwards (non-radial pulsations) and that the star expands and contracts in order to keep its spherical shape (radial pulsations), which causes changes in its size. Instead, when it comes to the end of its life, it will cast off its outer layers into space and gradually fade away as a white dwarf.Ĭaph is classified as a Delta Scuti variable, a star that exhibits changes in brightness due to both radial and non-radial pulsations. The star is not massive enough to be a supernova candidate. In the not-so-distant astronomical future, it will evolve into a red giant.

It has now likely burned through the supply of hydrogen in its core and is currently in the process of cooling and expanding. Its estimated age is between 1.09 and 1.18 billion years.Ĭaph started its life as a white, class A main sequence star with about twice the Sun’s mass. With a surface temperature of 7,079 K, Caph is 27.3 times more luminous than the Sun. The star has a mass of 1.91 solar masses and a radius that changes from 3.43 to 3.69 solar radii due to pulsations. Star typeĬaph has the stellar classification F2 III, indicating a giant star appearing white in colour. It is the rightmost star of Cassiopeia’s W, a familiar bright asterism formed by the constellation’s five brightest stars. Caph lies at a distance of 54.7 light years from Earth. With an average apparent magnitude of 2.28, it is the third brightest star in Cassiopeia, after Gamma Cassiopeiae and Schedar (or the second brightest star when the variable Gamma Cassiopeiae dims). Caph, Beta Cassiopeiae (β Cas) is a white giant star located in the constellation Cassiopeia.

Cassiopeia stars