Zalmoxis

Interior structure solver for rocky planets and sub-Neptunes.

Zalmoxis computes self-consistent radial profiles of density, pressure, temperature, gravity, and phase state for differentiated planets from 0.1 to 50 Earth masses. Given a total mass, layer composition, and temperature mode, it iteratively solves the coupled hydrostatic equilibrium equations to determine the planet's radius and internal structure.

Features

• Multiple EOS families: PALEOS unified tables (iron, MgSiO3, H2O), Chabrier H2 for sub-Neptune interiors, Wolf & Bower 2018, Seager 2007, and analytic polytropes
• Multi-material mixing: volume-additive harmonic mean with per-component phase-aware suppression
• H2 miscibility: binodal suppression models for H2-silicate and H2-H2O phase boundaries
• Temperature modes: adiabatic (self-consistent), isothermal, linear, or prescribed profiles
• Parameter grids: sweep any combination of input parameters via TOML grid files

Quick start

# Install
git clone https://github.com/FormingWorlds/Zalmoxis.git
cd Zalmoxis
pip install -e .

# Download EOS data
bash tools/setup/get_zalmoxis.sh

# Run default config (1 Earth-mass, PALEOS iron + MgSiO3)
python -m zalmoxis -c input/default.toml

See the installation guide and usage guide for details.

Documentation

Full documentation: proteus-framework.org/Zalmoxis

• Getting started
• Configuration reference
• EOS physics
• Mixing & binodal suppression
• API reference

Part of PROTEUS

Zalmoxis is the interior structure module of the PROTEUS framework for coupled atmosphere-interior evolution of rocky planets and sub-Neptunes.

Contributing

Contributions are welcome. Please read the Code of Conduct and contributing guidelines before opening a pull request. If you encounter issues, please open an issue.

License

Apache License 2.0