Warm Jupiters around M-dwarfs are great opportunities for extensive chemical, cloud and haze characterisation with JWST

TL;DR

Warm Jupiters orbiting M-dwarfs offer exceptional opportunities for atmospheric characterization with JWST, enabling detailed study of clouds, hazes, and chemical compositions, including potential NH3 detection, which enhances understanding of planetary atmospheres.

Contribution

This study demonstrates the potential of JWST to characterize clouds, hazes, and chemical compositions of warm Jupiters around M-dwarfs using 3D climate models and spectral simulations.

Findings

Spectral phase curves reveal cloud and haze presence.

Transit spectra allow detection of multiple chemical species.

NH3 could be detected for the first time in such exoplanets.

Abstract

The population of short-period giant exoplanets around M-dwarf stars is slowly rising. These planets present an extraordinary opportunity for atmospheric characterisation and defy our current understanding of planetary formation. Furthermore, clouds and hazes are ubiquitous in warm exoplanets but their behaviour is still poorly understood. We study the case of a standard warm Jupiter around a M-dwarf star to show the opportunity of this exoplanet population for atmospheric characterisation. We aim to derive the cloud, haze, and chemical budget of such planets using JWST. We leverage a 3D Global Climate Model, the generic PCM, to simulate the cloudy and cloud-free atmosphere of warm Jupiters around a M-dwarf. We then post-process our simulations to produce spectral phase curves and transit spectra as would be seen with JWST.We show that using the amplitude and offset of the spectral phase curves, we can directly infer the presence of clouds and hazes in the atmosphere of such giant planets. Chemical characterisation of multiple species is possible with an unprecedented signal-to-noise ratio, using the transit spectrum in one single visit. In such atmospheres, NH3 could be detected for the first time in a giant exoplanet. We make the case that these planets are key to understanding the cloud and haze budget in warm giants. Finally, such planets are targets of great interest for Ariel.