On October 19th the ESA confirmed its intention to launch an Exoplanet-hunting telescope called CHEOPS – CHaracterising ExoPlanet Satellite.
Unlike Kepler, primarily concerned with finding exoplanets, CHEOPS will instead focus on those exoplanets already found, focussing on those around bright local stars like the exoplanet found around Alpha Centauri B that we covered last week looking for evidence of more transits to help characterise the exoplanets orbital period and diameter.
In combination with observations of an exoplanet by the radial-velocity method to obtain a planets mass, knowing the diameter of the exoplanet will allow the planets approximate density to be calculated, allowing indications of the planet’s internal structure – for instance whether a planet is rocky like Earth or a gas giant like Jupiter.
This information can then help to characterise planetary system development in solar systems like our own.
Cheops will be implemented as a partnership between ESA and Switzerland, with a number of other ESA Member States delivering substantial contributions. Cheops is the first of a possible new class of small missions to be developed as part of ESA’s Science Programme. By concentrating on known stars with exoplanets around them, the size and cost of the mission is significantly reduced – the current design for CHEOPS has a primary mirror diameter of only 30cm compared to Kepler’s 95cm.
It is anticipated to launch in 2017 and orbit Earth at an altitude of 800km for 3.5 years while it completes its mission.