APIC

Free access article

Issue		A&A Volume 500, Number 3, June IV 2009


Page(s)		1277 - 1280
Section		Astronomical instrumentation
DOI		http://dx.doi.org/10.1051/0004-6361/200811232
Published online		16 April 2009

A&A 500, 1277-1280 (2009)
DOI: 10.1051/0004-6361/200811232

Research Note

Absolute Position Interfero-Coronagraph for direct exoplanet detection

F. Allouche^{1, 2}, A. Glindemann¹, E. Aristidi², and F. Vakili²

¹ ESO, European Organization for Astronomical Research in the Southern Hemisphere, Karl-Schwarzschild Strasse 2, 85748 Garching bei Mnchen, Germany
e-mail: fatme.allouche@eso.org
² Laboratoire H. Fizeau, Université de Nice Sophia-Antipolis, CNRS UMR 6526, Parc Valrose, 06108 Nice Cedex 2, France

Received 27 October 2008 / Accepted 13 March 2009

Abstract
Context. For detecting and directly imaging exoplanets, coronagraphic methods are mandatory when the intensity ratio between a star and its orbiting planet can be as large as 10⁶. In 1996, a concept of an achromatic interfero-coronagraph (AIC) was presented for detecting very faint stellar companions, such as exoplanets.
Aims. We present a modified version of the AIC not only permitting these faint companions to be detected but also their relative position to be determined with respect to the parent star, a problem that was not solved in the original design of the AIC.
Methods. In our modified design, two cylindrical lens doublets were used to remove the 180° ambiguity introduced by the AIC's original design.
Results. Our theoretical study and the numerical computations show that the axis of symmetry is destroyed when one of the cylindrical doublets is rotated around the optical axis.

Key words: methods: observational -- techniques: high angular resolution -- techniques: interferometric -- stars: binaries: close

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