# Characterizing Transiting Exoplanets with JWST Guaranteed Time and ERS Observations

## TL;DR

This paper discusses how JWST's guaranteed time and early release science observations will significantly enhance our understanding of exoplanet atmospheres, compositions, and climate, especially for warm-to-hot gas giants, during its first year.

## Contribution

It provides a detailed overview of the expected scientific advancements from JWST GTO and ERS observations of 27 transiting exoplanets, highlighting new insights into atmospheric properties.

## Key findings

- Insights into exoplanet atmospheric composition and chemistry
- Understanding of clouds and thermal profiles of gas giants
- Potential early clues about rocky planet atmospheres

## Abstract

We highlight how guaranteed time observations (GTOs) and early release science (ERS) will advance understanding of exoplanet atmospheres and provide a glimpse into what transiting exoplanet science will be done with JWST during its first year of operations. These observations of 27 transiting planets will deliver significant insights into the compositions, chemistry, clouds, and thermal profiles of warm-to-hot gas-dominated planets well beyond what we have learned from HST, Spitzer, and other observatories to date. These data and insights will in turn inform our understanding of planet formation, atmospheric transport and climate, and relationships between various properties. Some insight will likely be gained into rocky planet atmospheres as well. JWST will be the most important mission for characterizing exoplanet atmospheres in the 2020s, and this should be considered in assessing exoplanet science for the 2020s and 2030s and future facilities.