Discovery of a bipolar and highly variable mass outflow from the symbiotic binary StHα 190

Abstract

A highly and rapidly variable bipolar mass outflow from StHα 190 has been discovered, the first time in a yellow symbiotic star. Permitted emission lines are flanked by symmetrical jet features and multi-component P-Cyg profiles, with velocities up to 300 km s-1. Given the high orbital inclination of the binary, if the jets leave the system nearly perpendicular to the orbital plane, the de-projected velocity equals or exceeds the escape velocity (1000 km s-1). StHα 190 looks quite peculiar in many other respects: the hot component is an O-type sub-dwarf without an accretion disk or a veiling nebular continuum and the cool component is a G7 III star rotating at a spectacular 105 km s-1, unseen by a large margin in field G giants.