Exploring Earth Analog Atmospheres with the James Webb Space Telescope

The search for life outside our solar system initially requires exploring potentially habitable Earth-analog exoplanets. The James Webb Space Telescope (JWST), scheduled to launch in 2021, will be able to detect the atmospheres of these potential Earth-analog worlds. Thus, it is imperative that we optimize the use of JWST by developing observational strategies to efficiently characterize potentially habitable Earth-like exoplanets. To develop these strategies, we identified target planetary systems for JWST analysis, determined optimal configurations of JWST instruments for characterization of Earth-analog exoplanets, and estimated the number of transits required to detect key spectral features on our target worlds. This was accomplished by simulating atmospheric observations of Earth-analog exoplanets around a sequence of K and M stars with a variety of JWST instruments. We found that Earth-analog planets around M8V, M5V, and M2V stellar hosts yield the strongest overall spectral features for detection by a wide range of JWST observing modes. Furthermore, an analysis of key spectral features, H₂O at 1.4 and 2.5 microns, CH₄ at 3.3 and 8.0 microns, and CO₂ at 4.5 microns, was performed around the aforementioned planetary systems. Here we discuss the results of this analysis, specifically the number of transits required to detect these features, and the optimal combination of JWST instruments for their detection.