CORGI (Composition Of Rocky, Gaseous, and Icy planets) is a code package for planetary interior simulations. It has several modules useful for simulating the interior composition, structure, and gravity harmonics of all kinds of planets:
- A forward planet interior structure module capable of generating both distinct-layer and empirical density planet models.
- An inverse module for retrieving the possible compositions of a planet given its mass and radius using MCMC.
- A gravity harmonics module adopting the concentric Maclaurin spheroid (CMS) method (Hubbard 2013).
The basic functionalities of CORGI depends only on some standard Python libraries including numpy, scipy, matplotlib, pandas, datetime, and tqdm. The retrieval module relies on emcee. To run some codes in parallel to speed things up, the built-in multiprocessing module is helpful.
Below are the versions of my libraries. If you would like to create a new environment for CORGI (recommeneded), you can start with this set of libraries (I am using Python 3.8.20). Refer to this link for how to manage environments.
| Name | Version |
|---|---|
| emcee | 3.1.6 |
| matplotlib | 3.7.5 |
| matplotlib-inline | 0.1.7 |
| numpy | 1.21.0 |
| numpydoc | 1.5.0 |
| pandas | 1.2.3 |
| scipy | 1.5.2 |
| tqdm | 4.67.1 |
Note that, because of the file size limits of Github, AQUA water equation of state (EOS) files are only available on Zenodo [Zenodo link].
This repository includes two Jupyter Notebook tutorials that go through some of the basic functionalities of CORGI. tutorial_forward_model.ipynb introduces the forward modeling component of CORGI. tutorial_MR_curves.ipynb introduces how to generate constant-composition mass-radius (M-R) curves with CORGI. The figure below shows M-R curves generated with CORGI, overplotted with masses and radii of confirmed exoplanets from the NASA Exoplanet Archive.
If you use CORGI in your work, please cite:
- Lin, Z., Seager, S., & Weiss, B. P. 2025, Planet Sci J, 6, 27 [ADS link].
Some other relevant works that used CORGI are listed below:
- Lin, Z., Cambioni, S., & Seager, S. 2025, ApJL, 978, L41 [ADS link].
- Lin, Z., & Seager, S. 2025, ApJL, 990, L35 [ADS link]
- Lin, Z., & Daylan, T. 2026, under review [arXiv link].