Observing the Atmospheres of Known Temperate Earth-sized Planets with JWST

By C. Morley, Laura Kreidberg, Z. Rustamkulov, T. Robinson, Jon Fortney. 2017

234 citations recorded by the source corpus.

Nine transiting Earth-sized planets have recently been discovered around nearby late-M dwarfs, including the TRAPPIST-1 planets and two planets discovered by the MEarth survey, GJ 1132b and LHS 1140b. These planets are the smallest known planets that may have atmospheres amenable to detection with the James Webb Space Telescope (JWST). We present model thermal emission and transmission spectra for each planet, varying composition and surface pressure of the atmosphere. We base elemental compositions on those of Earth, Titan, and Venus and calculate the molecular compositions assuming chemical equilibrium, which can strongly depend on temperature. Both thermal emission and transmission spectra are sensitive to the atmospheric composition; thermal emission spectra are sensitive to surface pressure and temperature. We predict the observability of each planet’s atmosphere with JWST. GJ 1132b and TRAPPIST-1b are excellent targets for emission spectroscopy with JWST/MIRI, requiring fewer than 10 eclipse observations. Emission photometry for TRAPPIST-1c requires 5–15 eclipses; LHS 1140b and TRAPPIST-1d, TRAPPIST-1e, and TRAPPIST-1f, which could possibly have surface liquid water, may be accessible with photometry. Seven of the nine planets are strong candidates for transmission spectroscopy measurements with JWST, although the number of transits required depends strongly on the planets’ actual masses. Using the measured masses, fewer than 20 transits are required for a 5σ detection of spectral features for GJ 1132b and six of the TRAPPIST-1 planets. Dedicated campaigns to measure the atmospheres of these nine planets will allow us, for the first time, to probe formation and evolution processes of terrestrial planetary atmospheres beyond our solar system.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/29c79fc2c54ecf2b9d4e5d9caf4ef5255cc87b73

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

The Detectability and Characterization of the TRAPPIST-1 Exoplanet Atmospheres with JWST (2019, methodology): “Morley et al. (2017) used masses from Wang et al. (2017), with the exception of TRAPPIST-1f, for which the mass from Gillon et al. (2017) was used.”
Exoplanetary Atmospheres: Key Insights, Challenges, and Prospects (2019, background): “However, a more promising pathway that has emerged in recent years is the atmospheric characterisation of planets orbiting low-mass stars such as TRAPPIST-1 (92) and Proxima Centauri (5).”
Modeling climate diversity, tidal dynamics and the fate of volatiles on TRAPPIST-1 planets (2017, background): “In any case, each of these seven planets should be amenable to further characterization by the James Webb Space Telescope (JWST) as early as 2019 (Barstow & Irwin 2016; Morley et al. 2017).”