Speckle imaging of binary stars: Use of ratios of twofold probability density functions^*

Département d'Astrophysique de l'Université de Nice-Sophia Antipolis, Unité Mixte de Recherche 6525 du Centre Nationale de la Recherche Scientifique, Parc Valrose, 06108 Nice Cedex 2, France

Send offprint request to: M. Carbillet

Received: 18 November 1996
Accepted: 20 May 1997

Abstract

The probability imaging technique applied to double stars speckle data is presented within the framework of a new approach, giving more directly the intensity ratio and relative position of the components. The twofold probability density function is used for this purpose. A theoretical model is developed, pointing out a relevant quantity deduced from the twofold probability density functions of the binary system and a nearby reference star. A method using this quantity is proposed to reconstruct the binary system, together with a reference-less version of it. The practical implementation of the method is tested for limiting cases and is improved by numerical simulations. Making use of the resulting procedure, intensity ratios and relative positions of the components are obtained for three close binary stars: Del, Moaï  and γ Per.