Direct imaging
Direct imaging is the most intuitive method to search for exoplanets. It聽鈥渟imply鈥� aims at detecting the light emitted by the exoplanet. The difficulty is that the exoplanet is extremely faint compared to the brightness of the star it鈥檚 orbiting around. In order to be able to see聽the little dot representing the exoplanet one has to block the bright light from the star, which is usually achieved by using a coronograph.聽In addition to that, as the light from the exoplanet travels through the聽Earth atmosphere it gets smeared out so that adapative optics need to be聽used which correct for the atmosphere distortion in real time. The聽 instrument where Geneva is collaborating at is designed to聽directly image exoplanets. An alternative is to observe from space with聽telescopes such as Hubble or the upcoming JWST.
Once an exoplanet is discovered, its movement over the years can be聽monitored to determine its orbit. A precise mass can be determined for the companion when聽direct imaging is combined with measurements. In some聽cases an of the companion can also be acquired.
Two recent direct imaging results where the Geneva exoplanet group has聽contributed:
Direct imaging of the protoplanetary disk around HD142527 (Casassus et聽al., Nature, 2013)
A white dwarf companion to a rejuvenated star
(Zurlo et al., A&A 2013)