The (Exo)planet Opacity Database


To interpret next generation (exo)planet observations successfully and robustly, the community needs access to validated & up-to-date opacities. This was the motivation for the Molecules and Atoms in (Exo)planet Science: Tools and Resources for Opacities (MAESTRO) database, a NASA-supported opacity service that can be accessed by the community via a web interface. The MAESTRO project aims to develop community standards in computing and publishing opacity data. This is because subtle choices in opacities lead to model inconsistencies in the analysis of both high-resolution (R>10,000) and low resolution (James Webb Space Telescope-like) observations. MAESTRO is designed to help you find the data you need, as well as understand how the data was created.


  • Search for opacities by molecule or atom
  • Visualize opacity data
  • Compare opacities across temperature and pressure
  • Compare opacity across different molecules
  • Query and download opacity data
  • Automatic citation builders (BibTex and Overleaf)

Contribute to Opacities

Read the Contribution Guidelines to learn how to get involved.