PRELIMINARY-RESULTS OF DARK-SPECKLE STELLAR CORONOGRAPHY

The dark-speckle method (Labeyrie 1995) combines features of speckle i nterferometry and adaptive optics to provide images of faint circumste llar material. We present preliminary results of observations, and sim ulations concluding to the feasibility of exe-planet imaging from the ground. Laboratory simulations with an avalanche photodiode indicate t he detectability of a stellar companion of relative intensity 10(-6) a t 5 Airy radii from the star. New, more general, expressions for the s ignal-to-noise ratio and integration time are given. Comparisons with direct long-exposure imaging indicate that the method improves the det ectability of circumstellar nebulosity, faint companions and planets.