EDP Sciences
Free access
Volume 503, Number 1, August III 2009
Page(s) 301 - 308
Section Astronomical instrumentation
DOI http://dx.doi.org/10.1051/0004-6361/200811529
Published online 22 June 2009
A&A 503, 301-308 (2009)
DOI: 10.1051/0004-6361/200811529

Extreme coronagraphy with an adaptive hologram

Simulations of exo-planet imaging
D. Ricci1, H. Le Coroller2, and A. Labeyrie3

1  Département d'Astrophysique, Géophysique et Océanographie, Bât. B5C, Sart Tilman, Université de Liège, 4000 Liege 1, Belgium
    e-mail: ricci@astro.ulg.ac.be
2  Observatoire de Haute Provence, 04870 Saint Michel l'Observatoire, France
    e-mail: herve.lecoroller@oamp.fr
3  Collège de France, 11, place Marcelin Berthelot, 75231 Paris Cedex 05, France
    e-mail: antoine.labeyrie@obs-azur.fr

Received 16 December 2008 / Accepted 15 May 2009

Aims. We present a solution to improve the performance of coronagraphs for the detection of exo-planets.
Methods. We simulate numerically several kinds of coronagraphic systems, with the aim of evaluating the gain obtained with an adaptive hologram.
Results. The detection limit in flux ratio between a star and a planet $(F_{\rm s}/F_{\rm p})$ observed with an apodized Lyot coronagraph characterized by wavefront bumpiness imperfections of $\lambda$/20 (resp. $\lambda$/100) turns out to be increased by a factor of 103.4 (resp. 105.1) when equipped with a hologram.
Conclusions. This technique could provide direct imaging of an exo-Earth at a distance of 11 parsec with a 6.5 m space telescope such as the JWST with the optical quality of the HST.

Key words: instrumentation: detectors -- instrumentation: miscellaneous -- stars: planetary systems -- instrumentation: interferometers

© ESO 2009