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Preliminary results of dark-speckle stellar coronography

A. Boccaletti1 - A. Labeyrie2 - R. Ragazzoni3

1DESPA, Observatoire de Meudon, 5 place Jules Janssen 92195 Meudon, France,

2Collège de France & Observatoire de Haute Provence
04870 Saint Michel l'Observatoire, France

3Astronomical Observatory of Padova, vicolo del'Observatorio 5
I-35122 Padova, Italy

Astronomy & Astrophysics | Received 2 October 1997 ; accepted 22 January 1998


The dark-speckle method ([Labeyrie 1995]) combines features of speckle interferometry and adaptive optics to provide images of faint circumstellar material. We present preliminary results of observations, and simulations concluding to the feasibility of exo-planet imaging from the ground. Laboratory simulations with an avalanche photodiode indicate the detectability of a stellar companion of relative intensity 10-6 at 5 Airy radii from the star. New, more general, expressions for the signal-to-noise ratio and integration time are given. Comparisons with direct long-exposure imaging indicate that the method improves the detectability of circumstellar nebulosity, faint companions and planets.

Keywords: planetary systems - brown dwarfs - techniques: interferometric - binaries: close - stars: HD144217  


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