The Luminosity of the Classical Cepheid T VUL

Abstract

The classical Cepheid T Vul has been discovered to have a hot companion on International Ultraviolet Explorer satellite spectra. The companion has a spectral type of A0.8 V. The absolute magnitude of the Cepheid determined from the companion is M_v = -3.43 mag. Because the companion is significantly fainter and less massive than the Cepheid and the system has a very low reddening, this is a particularly well-determined luminosity. A high-accuracy velocity study would be valuable to look for orbital motion.