ExoTiC-LD: thirty seconds to stellar limb-darkening coefficients

TL;DR

ExoTiC-LD provides a rapid, thirty-second computational tool for deriving stellar limb-darkening coefficients, essential for precise exoplanet characterization, supporting multiple functional forms and reparameterizations.

Contribution

It introduces a fast, versatile software for calculating limb-darkening coefficients supporting various models and reparameterizations, improving efficiency in exoplanet studies.

Findings

Computes limb-darkening coefficients in thirty seconds

Supports multiple functional forms and reparameterizations

Facilitates accurate exoplanet characterization

Abstract

Stellar limb darkening is the observed variation in brightness of a star between its centre and edge (or limb) when viewed in the plane of the sky. Stellar brightness is maximal at the centre and then decreases radially and monotonically towards the limb -- hence the term "limb darkening". This effect is crucial for finding and characterising planets beyond our Solar System, known as exoplanets, as these planets are often studied when crossing in front of their host stars. As such, limb darkening is directly linked to the exoplanet signals. Limb darkening is typically modelled by one of various functional forms, as outlined in Claret (2000) and Sing (2010), and the coefficients of these functions is what ExoTiC-LD is designed to compute. A wide variety of functional forms are supported, including those benchmarked by Espinoza & Jord\'an (2016) as well as reparameterisations suggested by Kipping (2013).