BG Tri: an example of a low-inclination RW Sex-type nova-like
Gänsicke, B. T.; Steeghs, D.; Rodríguez-Gil, P.; Zharikov, S.; Aungwerojwit, A.; Tovmassian, G.; Hernández, M. S.
Chile, Mexico, Kazakhstan, United Kingdom, United States, Thailand, Spain
Abstract
We analyse a wealth of optical spectroscopic and photometric observations of the bright (V = 11.9) cataclysmic variable BG Tri. The Gaia DR2 parallax gives a distance d = 334(8) pc to the source, making the object one of the intrinsically brightest nova-like variables seen under a low orbital inclination angle. Time-resolved spectroscopic observations revealed an orbital period of $P_{\rm {orb}}=3.8028(24)$ h. Its spectroscopic characteristics resemble RW Sex and similar nova-like variables. We disentangled the H α emission line into two components, and show that one component forms on the irradiated face of the secondary star. We suggest that the other one originates at a disc outflow area adjacent to the L3 point.