Photometric analysis of two extreme low mass ratio contact binary systems

TL;DR

This study presents photometric analysis of two extreme low mass ratio contact binary systems, revealing their evolved secondary components, magnetic activity, and potential merger status, contributing to understanding of binary evolution.

Contribution

It provides detailed multi-band photometry and light curve analysis of two newly identified low mass ratio contact binaries, highlighting their evolutionary state and merger potential.

Findings

Both systems have extremely low mass ratios of 0.11 and 0.17.

The secondary stars show signs of advanced evolution with high densities.

TYC 6995-813-1 may be a merger candidate due to its proximity to the instability separation.

Abstract

Multi band photometry and light curve analysis for two newly recognized contact binary systems, TYC 6995-813-1 and NSVS 13602901 are presented. Both were found to be of extreme low mass ratios 0.11 and 0.17, respectively. The secondary components of both systems show evidence of considerable evolution with elevated densities as well as both luminosity and radii well above their main sequence counterparts. Even in the absence of significant spot activity at least one of the systems, TYC 6995-813-1, shows features of magnetic and chromospheric activity. TYC 6995-813-1 is also determined to be a potential merger candidate with its current separation near the theoretical instability separation.