Effective Temperature and the Light Curve Solution of Contact Binary Systems

TL;DR

This study demonstrates that the effective temperature of the primary star (T1) has minimal impact on light curve solutions of contact binary systems and explores using spectral energy distribution for T1 estimation.

Contribution

It shows that varying T1 within 1000K does not significantly affect light curve solutions and proposes using photometric spectral energy distribution as a standard for T1 assignment.

Findings

T1 variation within 1000K does not alter light curve solutions.

Spectral energy distribution can be used to estimate T1.

Light curve solutions are robust against T1 assignment uncertainties.

Abstract

With increasing number of contact binary discoveries and the recognition that luminous red novae are the result of contact binary merger events, there has been a significant increase in the number of light curve solutions appearing in the literature. One of the key elements of such solutions is the assignment and fixing of the effective temperature of the primary component (T1). Sometimes much is made of the assigned value with expectation of significantly different light curve solutions even though theoretical considerations suggest that absolute value of T1 has little influence on the geometric elements of the light curve solution. In this study we show that assigning T1 over a range of 1000K has no significant influence on the light curve solutions of two extreme low mass ratio contact binary systems. In addition, we explore the use of photometric spectral energy distribution as a potential standard for assigning T1 in the absence of spectroscopic observations.