ELLC - a fast, flexible light curve model for detached eclipsing binary stars and transiting exoplanets

TL;DR

ELLC is a new, fast, and flexible light curve model for analyzing detached eclipsing binary stars and transiting exoplanets, capable of handling complex effects and suitable for high-quality space-based data.

Contribution

The paper introduces ELLC, a novel light curve modeling tool that is accurate, versatile, and computationally efficient for detailed analysis of binary and exoplanet systems.

Findings

ELLC accurately models high-quality space photometry.

It effectively includes star spots, Doppler boosting, and light-travel time effects.

The model is fast enough for modern Monte Carlo data analysis.

Abstract

Very high quality light curves are now available for thousands of detached eclipsing binary stars and transiting exoplanet systems as a result of surveys for transiting exoplanets and other large-scale photometric surveys. I have developed a binary star model (ELLC) that can be used to analyse the light curves of detached eclipsing binary stars and transiting exoplanet systems that is fast and accurate, and that can include the effects of star spots, Doppler boosting and light-travel time within binaries with eccentric orbits. The model represents the stars as triaxial ellipsoids. The apparent flux from the binary is calculated using Gauss-Legendre integration over the ellipses that are the projection of these ellipsoids on the sky. The model can also be used to calculate the flux-weighted radial velocity of the stars during an eclipse (Rossiter-McLaughlin effect). The main features of the model have been tested by comparison to observed data and other light curve models. The model is found to be accurate enough to analyse the very high quality photometry that is now available from space-spaced instruments, flexible enough to model a wide range of eclipsing binary stars and extrasolar planetary systems, and fast enough to enable the use of modern Monte Carlo methods for data analysis and model testing.