October 10, 2023

About This Article

The Exoplanet Characterization ToolKit (ExoCTK), developed to aid researchers planning JWST observations for transiting exoplanetary science, has just released its version 1.2.5. The tool is now live through its suite of web-based services and associated Python package, and it’s officially supported by STScI.

This release includes the following updates:

  • The Contamination Overlap tool for NIRISS/SOSS incorporates the latest contamination modelling. This includes empirical distortion corrections of the contaminating traces, therefore improving its fidelity with real observations. In addition, identification of contaminants is done by querying the Gaia DR3 catalog instead of 2MASS. Finally, a new capability allows users to obtain detector-level simulations of contaminants, useful for both proposal planning and data analysis.
  • The JWST Visibility tool has been extended up to 2025.
  • The Limb Darkening Calculator now enables the calculation of limb-darkening accounting for light curve biases.
  • PandExo has been updated to Version 3.0, matching version 3.0 of the ETC and adding some user interface updates.

Observers who wish to update their current installation to ExoCTK 1.2.5 should also download the newest data packages associated with the release. Information on this and other installation instructions are available in the ExoCTK Github repository  and its associated ReadTheDocs documentation.

More information on this suite of tools can be found on JDox. Observers who need additional support installing or running ExoCTK should contact the JWST Help Desk using the Time Series Observations card.


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For technical assistance, please contact the JWST Help Desk.


The NASA James Webb Space Telescope, developed in partnership with ESA and CSA, is operated by AURA’s Space Telescope Science Institute.