Transient jets in V617 Sagittarii

Abstract

Context. Some of the luminous Compact Binary Supersoft X-Ray sources (CBSS) have shown indications of jets, also called satellites due to their appearance in the spectra. In V Sagittae (V Sge) stars, the galactic counterparts of the CBSS, such features have been reported only for WX Cen. Aims. If V Sge stars are indeed the analogs of CBSS, one may expect transient jet emission in other objects of this class. Methods. Spectroscopic observations of the V Sge star V617 Sgr have been made, both at high photometric state and at decline. Results. We show that V617 Sgr presents Ha satellites at high photometric state with velocities of ±780 km s -1 . Conclusions. This feature confirms, once more, the CBSS nature of the V Sge stars, however the details of the spectral characteristics also suggest that the two groups of stars display some intrinsic spectroscopic differences, which are likely to be due to a selection effect related to chemical abundance.