Fast thermochemical equilibrium solver that predicts which molecules and dust grains form in cosmic environments from scorching stellar atmospheres to frigid exoplanet clouds at 100K

Understanding what molecules exist in the vast temperature ranges of space—from the searing 3000K photospheres of stars to the bone-chilling 100K atmospheres of distant exoplanets—is fundamental to interpreting astronomical observations. Yet calculating chemical equilibrium across such extreme conditions, especially when gas-phase molecules condense into solid grains, presents a computational challenge that has limited our ability to model these environments accurately.

GGchem tackles this problem head-on with a fast thermochemical equilibrium code that determines molecular abundances, ion concentrations, and dust formation across temperatures from stellar to interstellar conditions. The code handles the complete periodic table (H through W), calculates electron densities assuming charge equilibrium, and crucially includes equilibrium condensation—predicting when and which solid particles form from the gas phase. It outputs everything astronomers need: molecular densities, supersaturation ratios, dust-to-gas mass ratios, and remaining gas-phase abundances, all customizable for different stellar abundance patterns.

Developed by Peter Woitke and Christiane Helling, this tool has become essential for exoplanet atmosphere modeling, stellar atmosphere analysis, and interstellar medium studies. Whether you’re predicting water vapor in hot Jupiter atmospheres, modeling dust formation in brown dwarf clouds, or calculating molecular line strengths for JWST observations, GGchem provides the chemical foundation that links theoretical models to observable reality.

⭐ Stars: 22
💻 Language: Roff
🔗 Repository: pw31/GGchem