Catwoman: A transit modelling Python package for asymmetric light curves

• Published in: arXiv.org
• Main Authors: Jones, Kathryn, Espinoza, Néstor
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 29.06.2021
• Subjects: Algorithms; Asymmetry; Chemical composition; Extrasolar planets; Light curve; Limb darkening; Physics - Earth and Planetary Astrophysics; Physics - Instrumentation and Methods for Astrophysics; Stellar surfaces; Transit
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2106.15643

When exoplanets pass in front of their stars, they imprint a transit signature on the stellar light curve which to date has been assumed to be symmetric in time, owing to the planet being modelled as a circular area occulting the stellar surface. However, this signature might be asymmetric due to different temperature/pressure and/or chemical compositions in the different terminator regions of the transiting planet. catwoman is a Python package that allows to model these asymmetric transit lightcurves, calculating lightcurves for any radially symmetric stellar limb darkening law, and where planets are modelled as two semi-circles, of different radii, using the integration algorithm developed in arXiv:1507.08285 and implemented in the batman library, from which catwoman builds upon.