A&A 389, 334-344 (2002)
DOI: 10.1051/0004-6361:20020419
Total coronagraphic extinction of rectangular apertures using linear prolate apodizations
C. Aime, R. Soummer and A. FerrariUMR 6525 Astrophysique, Faculté des Sciences, Université de Nice Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 2, France
e-mail: Claude.Aime@unice.fr, Andrea.Ferrari@unice.fr
(Received 25 July 2001 / Accepted 8 March 2002 )
Abstract
This paper presents a theoretical study of stellar
coronagraphy with apodized entrance apertures. The study is
restricted to a perfect telescope operating in space, and a
monochromatic on-axis unresolved star. It is shown that linear
prolate functions are the optimal apodizers for rectangular
apertures in stellar coronagraphy. With the phase mask technique
(Roddier & Roddier 1997), prolate functions can produce a total
extinction of the star light. For Lyot's coronagraphy, the
extinction is not complete, but prolate apodizations lead to an
optimal star residual intensity with surprising interesting
properties: the residual star light and the planet enjoy the same
apodized intensity pattern (but different dynamic) with the
optimal light concentration. With this technique, very high
rejection rates can be obtained for Lyot's coronagraphy, with
smaller mask sizes.
Key words: instrumentation: high angular resolution -- technique: high angular resolution -- stars: planetary systems
Offprint request: R. Soummer, Remi.Soummer@unice.fr
© ESO 2002