A method to identify and characterise binary candidates - a study of CoRoT data

TL;DR

This paper presents a novel method for identifying and characterizing binary star systems in CoRoT data by modeling transits to estimate system parameters without needing radial-velocity or ground-based observations.

Contribution

The study introduces a new modeling approach that accurately estimates binary system parameters directly from light curves, enhancing binary detection and characterization capabilities.

Findings

Validated method with known binaries and exoplanets.

Accurate parameter estimates for systems with secondary radii <1.5 Rjup or >2 Rjup.

Good agreement with published results for CoRoT exoplanetary systems.

Abstract

The analysis of the CoRoT space mission data was performed aiming to test a method that selects, among the several light curves observed, the transiting systems that likely host a low-mass star orbiting the main target. The method identifies stellar companions by fitting a model to the observed transits. Applying this model, that uses equations like Kepler's third law and an empirical mass-radius relation, it is possible to estimate the mass and radius of the primary and secondary objects as well as the semimajor axis and inclination angle of the orbit. We focus on how the method can be used in the characterisation of transiting systems having a low-mass stellar companion with no need to be monitored with radial-velocity measurements or ground-based photometric observations. The model, which provides a good estimate of the system parameters, is also useful as a complementary approach to select possible planetary candidates. A list of confirmed binaries together with our estimate of their parameters are presented. The characterisation of the first twelve detected CoRoT exoplanetary systems was also performed and agrees very well with the results of their respective announcement papers. The comparison with confirmed systems validates our method, specially when the radius of the secondary companion is smaller than 1.5 Rjup, in the case of planets, or larger than 2 Rjup, in the case of low-mass stars. Intermediate situations are not conclusive.