Simplified method for the identification of low mass ratio contact binary systems that are potential red nova progenitors

A Study of Six Extreme Low Mass Ratio Contact Binary Systems

“…Large scale high resolution radial velocity observations are at present impractical thus limiting our search for potential merger candidates among systems demonstrating total eclipses and therefore suitable for light curve analysis. To this end Wadhwa et al (2022b) have introduced simplified techniques to identify potential extreme low mass ratio system from survey photometric data. The present study continues our program of follow-up dedicated observations of potential merger candidates identified from such data.…”

“…It been well established that the secondary components have larger radii than main sequence stars of similar mass. Wadhwa et al (2022b) also reported that the radius of the primary may also be more than 25% larger than corresponding main sequence stars. In addition to change in the radii of the components some researchers (Yildiz & Doğan 2013) suggest that evolutionary mechanisms will likely lead to significant density variation between the components such that the secondary will always be denser and the the difference between density of the primary and secondary components (Δρ) will always be less than zero (Kähler 2004).…”

“…It has been known for some time that merger events and orbital instability in contact binaries is most likely when the mass ratio of the components (q = M 2 /M 1 ) is below some critical value (Rasio & Shapiro 1995;Arbutina 2007Arbutina , 2009. We have recently introduced methods to aid in the rapid identification of potential low mass ratio contact binary systems from survey photometry data (Wadhwa et al 2022b) in addition to a theoretical framework linking the mass of the primary component and geometric elements determined through light curve analysis to orbital instability (Wadhwa et al 2021).…”

“…This study reports photometric and spectroscopic observations of six poorly studied extreme low mass ratiocontact binary systems selected from the All Sky Automated Survey for SuperNovae (ASAS-SN) (Shappee et al 2014;Jayasinghe et al 2020). The systems were selected for observations based on the techniques described in Wadhwa et al (2022b) as being likely of low mass ratio and potentially unstable. Identification details for the systems are summarized in Table 1.…”

A Study of Twelve Potential Merger Candidate Contact Binary Systems

“…Although a number of studies, each with a large (10 or greater) number of contact binaries with extremely low mass ratios, have recently been reported they did not identify any system that meet the instability criteria (Gazeas et al 2021;Christopoulou et al 2022;Li et al 2022;Liu et al 2023). Wadhwa et al (2022) recently linked the amplitude of totally eclipsing contact binaries with the mass ratio which when used in conjunction with estimates of the mass of the primary can result in the rapid identification of potentially unstable systems. They identified over 40 new potential merger candidates based on the analysis of survey photometric data.…”