Issue |
A&A
Volume 435, Number 1, May III 2005
|
|
---|---|---|
Page(s) | 379 - 384 | |
Section | Astronomical instrumentation | |
DOI | https://doi.org/10.1051/0004-6361:20042424 | |
Published online | 25 April 2005 |
Combination of nulling interferometer and modified pupil for observations of exo-planets
1
MIRA project, National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588, Japan e-mail: jun.nishikawa@nao.ac.jp
2
LESIA, Observatoire de Paris, section Meudon, France e-mail: takayuki.kotani@obspm.fr
3
Department of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
4
Department of Applied Physics, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan e-mail: [naoshi;nbaba]@eng.hokudai.ac.jp
5
Graduate School of Science and Technology, Kobe University, Nada, Kobe 657-8501, Japan e-mail: yitoh@kobe-u.ac.jp
6
Optical and Infrared Division, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan e-mail: hide@subaru.naoj.org
Received:
26
August
2002
Accepted:
25
November
2004
We consider a combination of two techniques, namely the nulling interferometer and halo suppression by modified pupil such as shaped pupils and apodized square apertures, which achieves very high dynamic range, in order to detect faint extra-solar planets around nearby stars. The effects of the nulling interferometer and the modified pupil are independent and in combination hence multiplied. We show that one can achieve higher dynamic range in the case of a resolved star than with either method alone. By numerical simulations, we show that the combination method can achieve dynamic range levels of 10-10 at 3λ/D. Used alone, the two-telescope interferometer would give the nulling depth of 10-3 whilst the halo suppression by a shaped aperture would do 10-7, with a point-spread-function core radius less than 3λ/D for a shaped aperture. The introduction of the modified pupil has the same effect whether it is made at the entrance apertures of the interferometer or at a re-imaged common pupil plane after the nulling interferometry. From another point of view, a nulling interferometer works as pre-optics in front of any single telescope methods, which reduces the intensity of a resolved source transmitting some uniform wavefront residuals.
Key words: instrumentation: high angular resolution / techniques: interferometric / techniques: high angular resolution / telescopes / stars: planetary systems
© ESO, 2005
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