VULCAN

Photochemical kinetics for exoplanetary atmospheres, a fast and easy-to-use python code.

VULCAN can be used on its own, but is also integrated into the PROTEUS framework, a coupled simulation tool for the long-term evolution of atmospheres and interiors of rocky planets.

This distribution of VULCAN contains a number of performance and usability improvements.

• Demo with realtime plotting:

Contributors

Name	Email address
Shang-Min (Shami) Tsai	smtsai@asiaa.sinica.edu.tw
Harrison Nicholls	h-nicholls@pm.me
Karen Stuitje	e.k.e.stuitje@student.rug.nl

Project Structure

VULCAN/
├── vulcan.py                 # Main entry point
├── config.py                 # Configuration file (edit this!)
├── make_chem_funs.py         # Generates chemical functions
├── build_atm.py              # Atmospheric structure setup
├── op.py                     # Numerical operations & ODE solvers
├── store.py                  # Data storage & class definitions
├── phy_const.py              # Physical constants
├── agni.py                   # Additional utilities
├── paths.py                  # Path definitions
├── atm/                      # Atmospheric input files & stellar fluxes
├── fastchem_vulcan/          # FastChem equilibrium chemistry code
├── thermo/                   # Chemical networks & thermodynamic data
│   ├── NASA9/               # NASA-9 polynomial coefficients
│   ├── photo_cross/         # Photochemical cross sections
│   └── NCHO_photo_network.txt  # Default reaction network
├── cfg_examples/             # Example configuration files
├── tools/                    # Analysis and plotting utilities
├── output/                   # Output files (created at runtime)
└── plot/                     # Output plots (created at runtime)

Typically config.py is the only file you need to edit for each specific run. If you want to look inside or modify the code, store.py is where almost all classes and variables are declared.

Publications

The theory papers of VULCAN can be found here:

• Tsai et al. 2021 (with photochemistry)
• Tsai et al. 2017 (without photochemistry)