nemesispy 0.0.9

Tools for modelling exoplanet spectra

This library contains routines for simulating and fitting exoplanet emission spectra at arbitrary arbita orbital phase, thereby constraining the thermal structure and chemical abundance of exoplanet atmospheres. It is also capable of fitting emission spectra at multiple orbital phases (phase curves) at the same time. This package comes ready with some spectral data and general circulation model data so you could start simulating spectra straight away. There are a few demonstration routines in the nemesispy folder; in particular the demo_fit_eclipse.py contains an interactive plot routine which allows you to try to fit a hot Jupiter eclipse spectrum by hand by varying its chemical abundance and temperature profile. This package can be easily integrated with a Bayesian sampler, in particular MultiNest for a full spectral retrieval.

The radiative transfer calculations are done with the correlated-k approximation, and are accelerated with the numba just-in-time compiler to match the speed of compiled languages such as Fortran. The radiative transfer routines are based on the well-tested nemesis library developed by Patrick Irwin (University of Oxford) and collaborators.

This package has the following advantageous features:

• Highly portable and customisable compared to packages written in compiled languages, and can be easily installed on computer clusters.
• Fast calculation speed compared due to just-in-time compilation, which compiles Python code to machine code at run time.
• Radiative transfer routines are benchmarked against the extensively used nemesis library.
• Contains interactive plotting routines that allows you to visualise the impact of gas abundance and thermal structure on the emission spectra.
• Contains routine to simulate spectra from General Circulation Models (GCMs).
• Contains unit tests so that you could check if the the code is working properly after your modifications.