Prospects for Characterizing the Atmosphere of Proxima Centauri b

TL;DR

This paper explores how JWST thermal phase curve observations can determine the presence and characteristics of an atmosphere on Proxima Centauri b, aiding the search for extraterrestrial life.

Contribution

It demonstrates that JWST can distinguish between bare rock and atmospheric conditions on Proxima Centauri b using thermal phase curves and ozone detection.

Findings

JWST phase curves can differentiate between bare rock and atmospheric heat redistribution.

Ozone detection is feasible with longer JWST observations, indicating potential habitability.

Thermal observations can constrain the planet's atmospheric properties and habitability prospects.

Abstract

The newly detected Earth-mass planet in the habitable zone of Proxima Centauri could potentially host life - if it has an atmosphere that supports surface liquid water. We show that thermal phase curve observations with the James Webb Space Telescope (JWST) from 5-12 microns can be used to test the existence of such an atmosphere. We predict the thermal variation for a bare rock versus a planet with 35% heat redistribution to the nightside and show that a JWST phase curve measurement can distinguish between these cases at $4\sigma$ confidence, assuming photon-limited precision. We also consider the case of an Earth-like atmosphere, and find that the ozone 9.8 micron band could be detected with longer integration times (a few months). We conclude that JWST observations have the potential to put the first constraints on the possibility of life around the nearest star to the Solar System.