Emission line variability of RS Ophiuchi

We report that the H_alpha emission line of RS Oph was strongly variable during our 2004 observations on a time scale of 1 month. The line consisted of both a double peaked central narrow component (FWHM ~ 220 km/s) and a strongly variable broad one (FWHM ~ 2000 km/s). The base of the H_alpha line was very broad with FWZI 4600 km/s on all spectra from 1986 to 2004. The variability of the broad component extends from -2000 to +2000 km/s. Most probably this is due to either blobs ejected from the white dwarf (with a typical blob mass estimated to be ~10^{-10} M_solar or a variable accretion disk wind. We also detected variability of the HeII4686 line on a time scale shorter than 1 day. The possible origin is discussed.
accepted in MNRAS (letters)