Transient jets in V617 Sagittarii

TL;DR

This paper reports the detection of transient jet-like features in the V Sge star V617 Sgr, supporting its classification as a Compact Binary Supersoft X-Ray source and highlighting spectral differences within the class.

Contribution

It provides spectroscopic evidence of jet features in V617 Sgr, confirming its CBSS nature and suggesting intrinsic differences among V Sge stars.

Findings

Detection of Halpha satellites at +/-780 km/s in V617 Sgr

Confirmation of V Sge stars as CBSS analogs

Spectral differences possibly due to chemical abundance

Abstract

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. If V Sge stars are indeed the analogs of CBSS, one may expect transient jet emission in other objects of this class. Spectroscopic observations of the V Sge star V617 Sgr have been made, both at high photometric state and at decline. We show that V617 Sgr presents Halpha satellites at high photometric state with velocities of +/-780 km/s. 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.