Absolute magnitude (MV) −7 + −3.5 | Apparent magnitude (V) 7.02 - 9.20 | |
Similar Mu Cephei, RW Cephei, VV Cephei, T Cephei, Lambda Cephei | ||
W Cephei is a spectroscopic binary and variable star located in the constellation Cepheus. It is thought to be a member of the Cep OB1 stellar association at about 8,000 light years.
Contents
Discovery
W Cephei was reported in 1896 as a red star varying from magnitude 7.3 to 8.3. It was catalogued as BD+57°2568 in the Bonner Durchmusterung published in 1903, and HD 214369 in the Henry Draper Catalogue.
In 1925, W Cep was included in a listing of Be stars. It was recognised as a cool star with spectral type Mep. It was classified as K0ep Ia from a 1949 spectrum, but also recognised to have a small hot companion, plus an unusual infrared excess. Ultraviolet spectra allowed absorption lines from the companion to be studied and it was given a spectral type of B0-1.
System
The W Cephei system contains a K class supergiant star with a non-supergiant early B companion. The star has unusual emission lines including both permitted and forbidden FeII, produced by a circumstellar envelope containing dust and ionised gas. The two components have been resolved at 0.262" using Speckle interferometry. An orbital period of 2,090 days has been proposed.
Variability
W Cephei varies in brightness from 7th to 9th magnitude. The General Catalogue of Variable Stars lists it as a semiregular variable but attempts to find a period have shown only random variations.