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Volume 448, Number 2, March III 2006
Page(s) 787 - 800
Section Instruments, observational techniques, and data processing
DOI http://dx.doi.org/10.1051/0004-6361:20053516
A&A 448, 787-800 (2006)
DOI: 10.1051/0004-6361:20053516

Performance study of ground-based infrared Bracewell interferometers

Application to the detection of exozodiacal dust disks with GENIE
O. Absil1, R. den Hartog2, P. Gondoin2, P. Fabry2, R. Wilhelm3, P. Gitton3 and F. Puech3

1  Institut d'Astrophysique et de Géophysique, Université de Liège, 17 Allée du Six Août, 4000 Sart-Tilman, Belgium
    e-mail: absil@astro.ulg.ac.be
2  Science Payloads and Advanced Concepts Office, ESA/ESTEC, postbus 299, 2200 AG Noordwijk, The Netherlands
3  European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany

(Received 25 May 2005 / Accepted 2 November 2005)

Nulling interferometry, a powerful technique for high-resolution imaging of the close neighbourhood of bright astrophysical objets, is currently considered for future space missions such as Darwin or the Terrestrial Planet Finder Interferometer (TPF-I), both aiming at Earth-like planet detection and characterization. Ground-based nulling interferometers are being studied for both technology demonstration and scientific preparation of the Darwin/TPF-I missions through a systematic survey of circumstellar dust disks around nearby stars. In this paper, we investigate the influence of atmospheric turbulence on the performance of ground-based nulling instruments, and deduce the major design guidelines for such instruments. End-to-end numerical simulations allow us to estimate the performance of the main subsystems and thereby the actual sensitivity of the nuller to faint exozodiacal disks. Particular attention is also given to the important question of stellar leakage calibration. This study is illustrated in the context of GENIE, the Ground-based European Nulling Interferometer Experiment, to be installed at the VLTI and working in the L' band. We estimate that this instrument will detect exozodiacal clouds as faint as about 50 times the Solar zodiacal cloud, thereby placing strong constraints on the acceptable targets for Darwin/TPF-I.

Key words: instrumentation: high angular resolution -- instrumentation: interferometers -- techniques: interferometric -- circumstellar matter -- planetary systems

© ESO 2006