Establish which rocky exoplanets possess atmospheres

Determine which rocky exoplanets have atmospheres, focusing on the currently observed population accessible to JWST and HST, and identify the specific planets where an atmosphere is present versus absent to enable targeted follow-up studies.

Background

The report’s recommended Director’s Discretionary Time concept centers on secondary eclipse observations of rocky planets to infer dayside temperatures and heat redistribution, a robust proxy for the presence of an atmosphere. The authors emphasize that thermal emission measurements via JWST/MIRI 15 μm photometry avoid stellar contamination effects common in transmission spectroscopy and provide a more direct test of atmospheric existence.

This question is embedded within the broader scientific motivation to assess the prevalence and diversity of atmospheres on rocky M-dwarf planets and to delineate the "cosmic shoreline" demarcating atmospheric retention versus loss under varying stellar irradiation and planetary escape conditions.