CENTER TO LIMB DARKENING OF STARS - NEW MODEL AND APPLICATION TO STELLAR INTERFEROMETRY

Measurement of a star's apparent diameter with an intensity interferom eter yields its geometrical radius and its effective temperature when one knows or measures the specific centre to limb-darkening. This pape r presents a formulation that (1) makes use of a single parameter and (2) is well suited for the interpretation and comparison of centre to limb darkening. Subsequently, this result is applied to the study of t he contrast of the fringes as obtained with a stellar interferometer. A method yielding the angular diameter of the extended source together with the parameter of the law modeling its centre to limb darkening i s presented. The value of such observations made by GAIA type interfer ometer (Lindegren & Perryman 1996) are briefly noted in the last secti on.