A 4.86-h periodic modulation in the UV resonance lines of the cataclysmic variable V795 Herculis.

Abstract

Low-resolution IUE spectroscopy of V795 Her secured in 1992 August is used to authenticate the presence of an approximately 4.86-h periodic variation in the mainly wind-formed Si IV 1400-A and C IV 1549-A resonance lines. The modulation is demonstrated to be coherent across a 3-yr time-span, and is discordant with the mooted orbital (optical spectroscopic) period of about 2.60 h. Constraints are discussed for some possible configurations of the system that introduce asymmetries and can potentially yield modulated profile variability. The first ROSAT X-ray detection of V795 Her is also described.