Welcome to chemcomp’s documentation!

Modeling the chemical composition of gas giants by accretion of pebbles and gas. Before reading this documentation, please familiarise yourself with the following publications:

Schneider & Bitsch (2021a), Schneider & Bitsch (2021b)


chemcomp is a python code that aims to enable the study the formation of planets in 1D protoplanetary disks.

Included disk physics:

Included planet physics:


Phase 1: Dust particles grow to pebbles (small dots) and drift towards the star. Icy pebbles that cross the water ice line (dashed line) evaporate their water content and enrich the gas with water vapour. Water vapour that crosses the ice line condenses onto pebbles increasing their water content.


Phase 2: The core of the planet is formed by pebble accretion while the planet migrates. Depending on the formation path, the core composition can be icy or dry.


Phase 3: Once the planet is heavy enough to reach pebble isolation and form a pressure bump, pebbles are stoped and can not be accreted by the planet. The planet will then accrete water rich gas.

The physical model is in depth explained in (Schneider & Bitsch 2021a). This wiki is only meant for explanations on the structure of chemcomp.


  • Aaron Schneider would like to thank Bertram Bitsch for his enormous support during the development of this code and for continuing to use the code together with his students.

  • Aaron Schneider would like to thank Cornelis Dullemond for providing the solver which (in adapted version) is used to solve the gas viscous disk equation and dust transport equation.

  • Aaron Schneider would like to thank everyone, who has already used chemcomp in their work and has contributed in fixing small bugs.

Indices and tables

Copyright 2023 Aaron Schneider. Feel free to contact me for any questions via mail.