The Lowest Mass Planet with a Detected Atmosphere

The planet GJ 1214 b orbits a small, red dwarf star.

This is an excerpt from my post on Astrobites:

Title: Detection of the atmosphere of the 1.6 Earth mass exoplanet GJ 1132b
Authors:  John Southworth, Luigi Mancini, Nikku Madhusudhan, Paul Mollière, Simona Ciceri, and Thomas Henning
First Author’s Institution: Keele University (UK)
Status: Submitted, open access

With more and more exoplanets being discovered that border on potential habitability in terms of their size and temperature, the need to measure their atmospheres to test that habitability becomes more imperative.  Astronomers have been trying to measure exoplanet atmospheres for more than a decade with very mixed results.  Almost all of these studies have focused on hot Jupiters (typically 1,000-2,000 K), with GJ 1214 b, a cooler, lower mass planet (~550 K and 6.6 Earth masses) being a notable exception (and also with mixed results).  This new study, led by John Southworth of Keele University, marks one of the most ambitious attempts at measuring an exoplanet’s atmosphere:  a planet with just 1.6 times the mass of Earth at a temperature of just 600 K.