Reconstructed images of Alpha Orionis using stellar speckle interferometry

Abstract

We discuss a recently developed technique to recover nearly diffraction-limited images of supergiant stars such as α Orionis (Betelgeuse) from speckle interferometry data. This method relies on the digital identification and coaddition of the brightest individual speckles within a large number of short-exposure speckle photographs. The resulting average speckle may be thought of as the convolution of a point source speckle profile with the actual object intensity pattern. By making use of this point we have derived angular diameters and limb darkening coefficients in addition to finding evidence of possible surface structure on the star. The limitations of this technique have been determined empirically and they are discussed in this paper.