Project 3.5: Search and characterisation of transiting exoplanets
Our research group focuses on various key science questions in exoplanets that can be summarised in the following domains:
Search for terrestrial exoplanets
The search and characterisation of terrestrial exoplanets is at the frontier of the exoplanet field. Our team is involved in different areas to achieve the detection and study of potentially habitable planets. We are leading the SAINT-EX project that built and operates a 1-m telescope in Mexico. One goal of this observatory is to detect rocky exoplanets orbiting ultra-cool stars with the aim of characterising their surfaces and atmospheres within the next 5 to 10 years. To date, these planets represent our best chances to find life beyond Earth. Members of our team are part of the SPECULOOS collaboration that coordinates this survey from both hemispheres. We have also been playing a key role in the detection and characterisation of the TRAPPIST-1 system.
Characterisation of exoplanet atmospheres
Understanding the chemistry and climate of exoplanets is a major goal in exoplanet science. Our team leads several observing programmes with ground- (e.g. VLT, Magellan) and space-based (Hubble, Spitzer and Kepler space telescopes) facilities. The goals are to study the abundances of chemical species and the atmospheric circulation in ice and gas giant exoplanets. We have a close collaboration with the Exoplanets & Exoclimes Group at the CSH, led by Kevin Heng that results in fruitful synergies between exoplanet atmosphere theory and observations.
Small transiting exoplanets have found to be living in tightly-packed systems, where gravitational interactions between them play a paramount role in shaping the evolution and stability of these systems. Our team has pioneered a novel approach to study the intimate dynamics of these planets that enable us to measure the masses and densities of these planets. This in turn provides knowledge about their composition and their formation pathways. On this latter aspect, our collaborations with the planet formation groups led by Christoph Mordasini, Yann Alibert and Willy Benz are particularly fruitful.
Bayesian analyses of exoplanet populations
The field of exoplanets has long focused on individual targets. The recent advent of large exoplanet surveys such as the Kepler mission enables us to explore the physical properties of planets as a population. Our team has developed new tools to investigate trends in the thousands of exoplanets that have been found so far and that provide us information about e.g. the surface and atmospheric reflectivity (albedo) of these planets or new insights into the physical processes that drive inflated radii in close-in giant exoplanets.
CHEOPS science preparation
CHEOPS (Characterising Exoplanets Satellite) is the first ESA S-class mission and will be launched at the end of 2018. Several members of our team are involved in the Science Team and in different working groups that aims to render the mission a scientific success. Our prime interest is the characterisation of gaseous exoplanets at visible wavelengths to constrain albedos and dependence with longitude. We are also focussing on the search for small planets with CHEOPS and the complementarity from ground-based facilities such as the SAINT-EX Observatory. This work is done with the support of the NCCR PlanetS.