Beta Cephei type variability in the ultraviolet spectrum and radial velocity of PHL 346

Abstract

International Ultraviolet Explorer low-resolution and optical moderate-resolution spectra are presented for the high galactic latitude beta Cephei type star, PHL 346. Variability is identified in both the ultraviolet flux and the radial velocity with periods and phases consistent with those previously deduced from optical photometry. The similarity of both the flux and the radial velocity amplitude to those previously reported for the beta Cephei variable, gamma Pegasus, is striking and provides evidence for PHL 346 being a young core hydrogen burning star. A distance estimate for PHL 346 of approximately 7 kpc (corresponding to a z-distance of approximately 6 kpc) is obtained by scaling the distance of gamma Pegasus obtained from Hipparcos observations.