Letter to the Editor

Wavefront error correction and Earth-like planet detection by a self-coherent camera in space

¹ LESIA, Observatoire de Paris, CNRS and University Denis Diderot Paris 7, 5 place Jules Janssen, 92195 Meudon, France e-mail: [raphael.galicher;pierre.baudoz;gerard.rousset]@obspm.fr
² Groupement d'Intérêt Scientifique Partenariat Haute Résolution Angulaire Sol Espace (PHASE) between ONERA, Observatoire de Paris, CNRS and University Denis Diderot Paris 7, France

Received: 9 June 2008
Accepted: 6 July 2008

Abstract

Context. In the context of exoplanet detection, the performance of coronagraphs is limited by wavefront errors.

Aims. To remove efficiently the effects of these aberrations using a deformable mirror, the aberrations themselves must be measured in the science image to extremely high accuracy.

Methods. The self-coherent camera which is based on the principle of light incoherence between star and its environment can estimate these wavefront errors. This estimation is derived directly from the encoded speckles in the science image, avoiding differential errors due to beam separation and non common optics.

Results. Earth-like planet detection is modeled by numerical simulations with realistic assumptions for a space telescope.

Conclusions. The self-coherent camera is an attractive technique for future space telescopes. It is also one of the techniques under investigation for the E-ELT planet finder the so-called EPICS.