Catwoman: A transit modelling Python package for asymmetric light curves

Abstract

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.

3 pages, 1 figure. Published in JOSS

References in corpus (4)

• Analytic Lightcurves for Planetary Transit Searches
• batman: BAsic Transit Model cAlculatioN in Python
• STARRY: Analytic Occultation Light Curves
• Transit Signatures of Inhomogeneous Clouds on Hot Jupiters: Insights From Microphysical Cloud Modeling

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• A Panchromatic Characterization of the Evening and Morning Atmosphere of WASP-107 b: Composition and Cloud Variations, and Insight into the Effect of Stellar Contamination
• Tracing the formation and migration history: molecular signatures in the atmosphere of misaligned hot Jupiter WASP-94Ab using JWST NIRSpec/G395H
• Strong NUV Refractory Absorption and Dissociated Water in the Hubble Transmission Spectrum of the Ultra Hot Jupiter KELT-20 b
• Cloudy mornings and clear evenings on a gas giant exoplanet
• An Analytic Characterization of the Limb Asymmetry -- Transit Time Degeneracy
• ACCESS: Tentative detection of H${}_2$O in the ground-based optical transmission spectrum of the low-density hot Saturn HATS-5b
• Signature of the atmospheric asymmetries of hot and ultra-hot Jupiters in lightcurves
• Probing Two-dimensional Asymmetries of an Exoplanet Atmosphere from Chromatic Transit Variation
• KRONOS I: The $1-2.8\mu$m JWST Transmission Spectrum of the 23 Myr V1298 Tau c