Welcome to STCTM’s Documentation!

STCTM: the STellar ConTamination Modeling framework

stctm performs spectral retrievals on exoplanet transmission spectra and (out of transit) stellar spectra assuming the stellar surface can be explained by a combination of spectral components.

Previous Uses of the Code

• Lim et al., 2023 (TRAPPIST-1 b)

• Roy et al., 2023 (GJ 9827 d - HST)

• Piaulet-Ghorayeb et al., 2024 (GJ 9827 d - JWST/NIRISS SOSS)

• Radica et al., 2025 (TRAPPIST-1 c)

• Ahrer et al., 2025 (GJ 3090 b)

• Piaulet-Ghorayeb et al., 2025 (TRAPPIST-1 d)

Table of Contents

Contents:

• Installation instructions
  • Dependencies
  • Stellar model package installation
  • Required inputs: the stellar models grid
  • Testing your installation
• Create a grid of stellar models using MSG
• stctm retrievals: basic orienteering
  • Two types of retrievals
  • Input structure
  • Running a retrieval
  • Retrieval outputs
• Running your first TLS retrieval
  • The data
  • Run instructions
  • Modifying the TOML file to make it your own
  • Post-processing
• Running stellar spectrum retrievals with exotune
  • The data
  • Setting up an exotune retrieval: Run instructions
  • Modifying the TOML file to make it your own
  • Post-processing
• Citations
  • Additional Citations
• Contributing to STCTM
• API
  • Utility functions for TLS retrievals
  • Utility functions for stellar spectrum retrievals
  • Definition of stellar spectrum object
  • Definition of transmission spectrum object

Have fun!