Erebus documentation

Erebus is a rocky-exoplanet secondary eclipse aperture-photometry lightcurve fitting pipeline made for use with the Mid Infra-Red Instrument aboard the James Webb Space Telescope, starting with calints.fits files available on the Barbara A. Mikulski Archive for Space Telescopes. Optionally Erebus can be run starting with uncal.fits files, in which case it calls Eureka! to perform the first two stages of the pipeline. If you use this functionality, be sure to properly cite Eureka.

For issue reporting or feedback suggestions click here.

For the setup used when writing Connors et al. (2025) click here. For the setup used when writing Connors et al. (2026) for GJ 3929 b click here.

If you use Erebus in a scientific publication we will ask you cite our paper:

@ARTICLE{2025ApJ...989L..11C,
       author = {{Connors}, Nicholas J. and {Monaghan}, Christopher and {Benneke}, Bj{\"o}rn and {Dang}, Lisa},
        title = "{Uniform Reanalysis of JWST MIRI 15 {\ensuremath{\mu}}m Exoplanet Eclipse Observations Using Frame-normalized Principal Component Analysis}",
      journal = {\apjl},
     keywords = {Exoplanets, Exoplanet atmospheres, Planetary atmospheres, 498, 487, 1244, Earth and Planetary Astrophysics, Instrumentation and Methods for Astrophysics},
         year = 2025,
        month = aug,
       volume = {989},
       number = {1},
          eid = {L11},
        pages = {L11},
          doi = {10.3847/2041-8213/adee0d},
archivePrefix = {arXiv},
       eprint = {2507.02052},
 primaryClass = {astro-ph.EP},
       adsurl = {https://ui.adsabs.harvard.edu/abs/2025ApJ...989L..11C},
      adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

For other uses of Erebus you can cite:

@ARTICLE{2026ApJ..1006L...6C,
       author = {{Connors}, Nicholas J. and {Monaghan}, Christopher and {Benneke}, Bj{\"o}rn and {Dang}, Lisa and {Roy}, Pierre-Alexis},
        title = "{GJ 3929 b as the First Complete Rocky Worlds DDT Data Set}",
      journal = {\apjl},
     keywords = {Exoplanets, Exoplanet atmospheres, Planetary atmospheres, 498, 487, 1244, Earth and Planetary Astrophysics},
         year = 2026,
        month = jul,
       volume = {1006},
       number = {1},
          eid = {L6},
        pages = {L6},
          doi = {10.3847/2041-8213/ae8018},
archivePrefix = {arXiv},
       eprint = {2606.07511},
 primaryClass = {astro-ph.EP},
       adsurl = {https://ui.adsabs.harvard.edu/abs/2026ApJ..1006L...6C},
      adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

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Changelog

0.8.1

• Hotfix: FNPCA joint fit was broken.

0.8.0

• Added helper methods to run Eureka stage 1 and 2 when starting from uncal files before using Erebus.
• Added setting to fit no eclipse
• Added settings for gaussian/uniform prior on eclipse timing
• Record log likelihood and BIC
• Allow setting custom systematic model for Erebus to detrend with
• Numerous bug fixes
• Version used in Connors et al. 2026

0.7.1

• Now uses ecosw and esinw instead of e and w
• Add optional setting to fix eclipse timing
• Improved convergence checking
• Version used in Connors et al. 2025

0.7.0

• Pre-processing of calints data for NaN and outlier rejection.
• Light curve fitting using FN-PCA, exponential ramp, or custom systematic model
• Fits for orbital parameters within provided errors. Support for t0 predictions from lookup file.