An Etymological Dictionary of Astronomy and Astrophysics

The second brightest star in the constellation → Cepheus and the prototype of → Beta Cephei variables. It is a variable B2 type → giant star with a visual magnitude of 3.23 varying with a period of 4.57 hours. Its mass is a dozen times that of the Sun. Beta Cephei is a → triple system lying at a distance of about 600 → light-years. The inner → spectroscopic companion, → spectral type A, is only about 45 AU away, and takes around 90 years to orbit. The third visual companion is at least 2400 AU away, with an orbital period of at least 30,000 years.

See also: Beta (β), the second letter of the Gk. alphabet; → Cepheus.