Identifying Candidate Atmospheres on Rocky M dwarf Planets via Eclipse Photometry

Understand

Most rocky planets in the galaxy orbit a cool host star, and there is large uncertainty among theoretical models whether these planets can retain an atmosphere.

• The James Webb Space Telescope (JWST) might be able to settle this question empirically, but most proposals for doing so require large observational effort because they are based on spectroscopy.
• Here we show that infrared photometry of secondary eclipses could quickly identify "candidate" atmospheres, by searching for rocky planets with atmospheres thick enough that atmospheric heat transport noticeably reduces their dayside thermal emission compared to that of a bare rock.
• For a planet amenable to atmospheric follow-up, we find that JWST should be able to confidently detect the heat redistribution signal of an O(1) bar atmosphere with one to two eclipses.