BG Tri an example of a low inclination RW Sex-type novalike

TL;DR

This study presents detailed optical spectroscopic and photometric analysis of BG Tri, a bright, low-inclination nova-like cataclysmic variable, revealing its orbital period, spectral features, and emission line origins.

Contribution

It provides the first detailed spectroscopic characterization of BG Tri, including orbital period and emission line analysis, highlighting its similarities to RW Sex-type novalike variables.

Findings

Orbital period of 3.8028 hours determined.

Spectroscopic features resemble RW Sex and similar novalike variables.

Disentangled H alpha emission into two components, one from the secondary star and another from disc outflow.

Abstract

We analysed a wealth of optical spectroscopic and photometric observations of the bright (V=11.9) cataclysmic variable BG Tri. TheGaiaDR2 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 the orbital period of P(orb)=3.h8028(24). Its spectroscopic characteristics resemble RW Sex and similarnova-like variables. We disentangled the H alpha 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.