Coronagraphic search for exo-planets with a hypertelescope

Abstract

Abstract. Following the idea developed in Boccaletti et al. (2000), a snapshot imaging interferometer is proposed as an alternative to the nulling interferometer for the NASA Origin project, "Terrestrial Planet Finder". This concept is based on hypertelescope, i.e. densified-pupil, imaging (Labeyrie 1996) and phase-mask coronagraphy (Rouan et al. 2000) to combine a very high angular resolution and a deep attenuation of starlight (10 −8 ) as required to image extra-terrestrial planets. This article aims at presenting thorough estimations of the signal to noise ratio for different classes of stars (from F0V to M5V) and includes several sources of background noise (zodiacal and exozodiacal lights for instance). In addition, numerical simulations have been carried out and are compared to the analytical results. We find that the image of Earth-like planets can be formed with a large hypertelescope (∼80 m) in the thermal infra-red for about 73% of the stars within 25pc.

The Four‐Quadrant Phase Mask Coronagraph. III. Laboratory Performance

“…A complete study was performed by Riaud et al (2002) to demonstrate the performance of an FQPM with a densifiedpupil interferometer in space (Labeyrie 1996).…”

Combining Coronagraphy With Interferometry as a Tool for Measuring Stellar Diameters

“…Combination of these two techniques (interferometry and coronagraphy, or equivalently, nulling interferometry) is generally used to improve the detection of faint structures or companions around nearby stars (Riaud et al 2002;Tinetti 2006;Wallner et al 2006). Given the fact that coronagraphic devices are sensitive to the angular source size, a coronagraphic implementation of a stellar interferometer can further improve the detection variations of stellar sources diameters.…”

Imaging capabilities of hypertelescopes with a pair of micro-lens arrays

“…Direct imaging occurs within the unaliased narrow field of view (ZOF) and the images are usable for spectroscopic, spectro-imaging and also coronagraphic uses with a focal mask such as Roddier's phase dot or Rouan's Four Quadrant Phase Mask . A hypertelescope coupled to a coronagraph has been proposed for NASA's Terrestrial Planet Finder project (Riaud et al 2002). The concept is being further explored in our group.…”

“…The principle of densified-pupil multi-aperture imaging interferometers, called hypertelescopes, was previously described (Labeyrie 1996;Gillet et al 2001;Riaud et al 2002). Let us consider light beams coming from N small mirrors arrayed periodically in two dimensions with period s. Beams from these mirrors are initially combined according to a Fizeau interferometer geometry.…”