2005MNRAS.363L..26Z

We report that the Hα emission line of RS Oph was strongly variable during our 2004 observations on a time-scale of one month. The line consisted of both a double-peaked central narrow component [full width at half-maximum (FWHM) ∼ 220 km/s] and a strongly variable broad one (FWHM > 2000 km/s). The base of the Hα line was very broad, with full width at zero intensity ~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 either to blobs ejected from the white dwarf (with a typical blob mass estimated to be ∼10^–10M_☉) or to a variable accretion disc wind. We also detected variability of the Heiiλ4686 line on a time-scale shorter than 1 d. The possible origin is discussed.