## The Project

Which molecules are present in the atmosphere of exoplanets? What are their mass, radius and age? Do they have clouds, convection (atmospheric turbulence), fingering convection, or a circulation induced by irradiation? These questions are fundamental in exoplanetology to better understand planet formation and exoplanet habitability with JWST.

« James Webb Space Telescope will tell us more about the atmospheres of extrasolar planets, and perhaps even find the building blocks of life elsewhere in the universe. »

This project aims at characterizing the impact of fingering convection in the atmosphere of stars, brown dwarfs, and exoplanets and its interaction with the circulation in the case of irradiated planets. By developing innovative numerical models, we will characterize the effect of the fingering instability induced by chemical transitions (e.g. CO/CH$$_4$$) and the impact of the circulation induced by irradiation on this instability. We will then predict and interpret the mass, radius, and chemical composition of exoplanets that will be observed with future missions such as the James Webb Space Telescope (JWST).

## What is fingering convection?

Fingering convection is a known phenomenon happening in Earth Oceans, that has been introduced in oceanography by Stern (1960) and in stellar astrophysics in the 70’s by Ulrich (1972). Recently it has been proposed to occur in the atmosphere of brown darfs and exoplanets (Tremblin et al. 2015 and Tremblin et al. 2016).

## News

### Pre-ERC result: Hubble Detects Exoplanet with Glowing Water Atmosphere

Image © NASA, ESA, and A. Feild (STSci) Exeter University Press release: Scientists have found unmistakable evidence for a stratosphere on an enormous planet outside our solar system, with an atmosphere hot enough to boil iron. An international team of researchers, led by the University of Exeter, made the new discovery by observing glowing water molecules in …

### Pre-ERC result: HAT-P-26b: A Neptune-mass exoplanet with a well-constrained heavy element abundance

A correlation between giant-planet mass and atmospheric heavy elemental abundance was first noted in the past century from observations of planets in our own Solar System and has served as a cornerstone of planet-formation theory. Using data from the Hubble and Spitzer Space Telescopes from 0.5 to 5 micrometers, we conducted in this Science paper, …

### Pre-ERC result: Advection of potential temperature in the atmosphere of irradiated exoplanets: a robust mechanism to explain radius inflation

The anomalously large radii of strongly irradiated exoplanets have remained a major puzzle in astronomy. In this new ApJ paper, based on a 2D steady state atmospheric circulation model, the validity of which is assessed by comparison to 3D calculations, we reveal a new mechanism, namely the advection of the potential temperature due to mass …

## Contact and Team

Contact

• Pascal Tremblin: Personal Website
• Phone: +33 1 69 08 59 67
• Email: pascal.tremblin[at]cea.fr

Team

• See opened positions here