RoadRunner: a fast and flexible exoplanet transit model

TL;DR

RoadRunner is a rapid, flexible exoplanet transit modeling tool that supports custom limb darkening functions and is optimized for CPU and GPU, enhancing efficiency and adaptability in transit analysis.

Contribution

It introduces a fast, customizable transit model that allows any radially symmetric limb darkening function, integrated into the PyTransit package with GPU acceleration.

Findings

Faster evaluation than traditional models for quadratic limb darkening

Supports complex, heterogeneous time series modeling

Includes a numerical limb darkening profile implementation

Abstract

I present RoadRunner, a fast exoplanet transit model that can use any radially symmetric function to model stellar limb darkening while still being faster to evaluate than the analytical transit model for quadratic limb darkening by Mandel & Agol (2002). CPU and GPU implementations of the model are available in the PyTransit transit modelling package, and come with platform-independent parallelisation, supersampling, and support for modelling complex heterogeneous time series. The code is written in numba-accelerated Python (and the GPU model in OpenCL) without C or Fortran dependencies, which allows for the limb darkening model to be given as any Python-callable function. Finally, as an example of the flexibility of the approach, the latest version of PyTransit comes with a numerical limb darkening model that uses LDTk-generated limb darkening profiles directly without approximating them by analytical models.