Robust spectral indices for exoplanets observed with JWST

James Webb Space Telescope (JWST) is expected to bring an opportunity for advancements in a broad range of astronomical fields, including exoplanet studies. With the growing number of detected exoplanets, especially in transits, it has become possible to study these objects as populations that can provide us with insights about how planets form and evolve. However, due to the high allocation time pressure, it is essential to be able to select optimal observing modes or extract the most useful information from already obtained data.

We created the first spectral indexing scheme for exoplanets that enables us to robustly measure their parameters (temperature, metallicity, and carbon-to-oxygen ratio) using fluxes at only 2-4 different wavelengths. Since our approach can compute results almost immediately, it has strong advantages over forward modeling and retrievals.  This will facilitate comparative studies for a large number of exoplanets observed with JWST.

I will present INDEXTER, the method for characterizing exoplanets using spectral indices. Furthermore, I will demonstrate the performance of INDEXTER when applied to real observations from the Hubble Space Telescope and modeled data for JWST. In conclusion, I will talk about the optimal JWST modes for observing exoplanets.

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