Studies of late-type binaries. II. The physical parameters of VW Cephei.

A spectroscopic/light curve study of VW Cephei yields a primary of 0.897 + or - 0.013 solar masses and 0.93 + or - 0.01 solar radii, a secondary of 0.247 + or - 0.007 solar masses and 0.50 + or - 0.01 solar radii, and a tertiary of 0.58 + or - 0.14 solar masses and 0.64 solar radii. Major period changes of -5.7 x 10 to the -6th in 1944, -6.8 x 10 to the -6th in 1950, 15.9 x 10 to the -6th in 1961 have occurred. A comparison of the derived physical parameters with the data of Hilditch et al. (1988) suggests that VW Cep AB is a W-type system and that the tertiary is a main-sequence object.