Astronomy seminar - Exoplanet discovery and characterisation

Observations during the last decade have uncovered large populations of exoplanets without any counterparts in our own planetary system. This diversity has been one of the major discoveries. One of the most powerful tools in the hunt for new exoplanets is dedicated space mission surveys using the technique of ultra-high precision transit photometry. This allows not only discoveries of new planets, but also measurements of the radius relative to the host star and orbital parameters. By combining the photometry from space missions with ground-based radial velocity measurements, true planet masses and bulk densities can be obtained. But although more than 4000 exoplanets have been detected to date, mainly by the Kepler space telescope, far fewer have been fully characterised and hence the composition and internal structure for most exoplanets are unknown. Only a few tens of Super-Earths have been securely identified. This paucity is related to the faintness of the target stars and a new generation of spacecrafts is therefore specifically targeting bright stars. NASA’s TESS spacecraft, launched in April 2018, is an all sky survey mission of short period planets orbiting bright stars which will enable precise follow-up observations. CHEOPS (Characterising Exoplanet Satellite), to be launched 17 Dec 2019, is a European mission equipped with ultra-high precision photometers. The targets will be bright stars already known to host exoplanets and will be observed individually. The European PLATO mission with a launch in 2026 is a next-generation planet-hunter with an emphasis on rocky planets in the habitable zone around solar-type stars.
In this talk, I will give an overview of our work at Chalmers and the collaboration with the international KESPRINT consortium.