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Proceedings Paper

Adaptive optics and site requirements for the search of Earth-like planets with ELTs
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Paper Abstract

Since 1995, expolanets discoveries have triggered a renewal of the permanent question about the possible presence of life outside the solar system. Direct detection and characterization of earth-like extrasolar planets orbiting main-sequence stars are now among the most exciting and challenging astronomical topics where new major scientific results from space missions and also from ground-based ELT are expected. To scale the performances of an ELT for exoplanets searching, we examine the relative impact of three fundamental parameters (the actuator pitch, the telescope diameter and the site) on the image contrast. Then, we calculate the planet/star flux ratio needed to reach SNR=3 in 10h (only the photon noise is considered) from long-exposure AO-PSF computed with PAOLA (a fast analytical code developed by one of us: L.J.) for different ELT sizes and AO parameters under different observational conditions (atmospheric turbulenece, star magnitude) with or without coronagraphy. We find that an actuator pitch of 0.1 m is optimal for exoplanet searching in the visible and near-IR from 10 to 40 pc. Lastly, we emphasize that the site choice is as important as the telescope size choice is: a 15m telescope is just enough for coronagraphic search for exo-earths at 10pc (SNR=3 in 10h) from the promising Dome C (Antarctica), while a 30m ELT is needed to succeed the same observation in the same time from the Mauna Kea.

Paper Details

Date Published: 7 July 2004
PDF: 10 pages
Proc. SPIE 5382, Second Backaskog Workshop on Extremely Large Telescopes, (7 July 2004); doi: 10.1117/12.566273
Show Author Affiliations
Olivier Lardiere, Osservatorio Astrofisico di Arcetri (Italy)
Piero Salinari, Osservatorio Astrofisico di Arcetri (Italy)
Laurent Jolissaint, Herzberg Institute of Astrophysics/National Research Council (Canada)
Marcel Carbillet, Osservatorio Astrofisico di Arcetri (Italy)
Armando Riccardi, Osservatorio Astrofisico di Arcetri (Italy)
Simone Esposito, Osservatorio Astrofisico di Arcetri (Italy)

Published in SPIE Proceedings Vol. 5382:
Second Backaskog Workshop on Extremely Large Telescopes
Arne L. Ardeberg; Torben Andersen, Editor(s)

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