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  • Illustration exoplanets.
  • Illustration CHEOPS. Credits: ESA.

Characterising exoplanets

CHEOPS is the first mission dedicated to studying bright, nearby stars that are already known to host exoplanets, in order to make high-precision observations of the planet's size as it passes in front of its host star. It focuses on studying planets in the super-Earth to Neptune size range.

An ESA mission for exoplanets

The CHaracterizing ExOPlanet Satellite (CHEOPS) is the first ESA S-type mission, and is the first to search for transits by means of ultrahigh precision photometry on bright stars already known to host planets, and was launched in December 2019. Among the planets observed by CHEOPS, super-Earths take a privileged position. They are the larger and more massive siblings of our Earth but will permit many studies of processes that are extremely relevant and important to the structure and evolution of our atmosphere. CHEOPS will identify planets with significant atmospheres in a range of masses, distances from the host star, and stellar parameters. Using observations of a sample of planets with and without significant gaseous envelopes, CHEOPS will be able to constrain the critical core mass (in the case of runaway gas accretion) or the loss of primordial H/He atmospheres as a function of the distance to the star and possibly stellar parameters (mass, metallicity).

Illustration exoplanets.

ICE-CSIC's participation

ICE-CSIC is involved in the scientific aspects of the CHEOPS mission through its participation in the Mission Board and Core Science Team.


Senior institute members involved

Meet the senior researcher who leads our participation in the CHEOPS mission.


  • Ignasi Ribas