Exoplanets

One of the most ambitious goals of modern astronomy is the detection of signs of biological activity beyond Earth. One way to achieve this objective is to make spectroscopic measurements of the light emitted by Earth-like exoplanets and to look for specific molecules and bio-signatures in their possible atmosphere.

The low number of photons to be gathered from the planets, the high intensity contrast with the star, and the small angular resolution are the major difficulties for direct detection. However, nulling interferometry is a solution to tackle these challenges. By combining the light of two or more telescopes, the angular resolution would considerably increase and thus could potentially lead to the detection of Earth-size rocky exoplanets around Solar-type stars. Moreover, with a π-phase shift between the two interferometer arms, the starlight is largely reduced. This allows the detection of much fainter objects around the star. The contrast between a planet and a star is the limiting factor for any direct detection. For example, the Earth/Sun pair has a contrast of 10^-9 in the visible and 10^-6 in the infrared. It has been proven that nulling interferometry can reduce stellar flux to allow any detection.

The space instrumentation section develops space interferometric nulling instruments capable of directly detecting and characterizing nearby exoplanets.