DIVA - AN INTERFEROMETRIC MINISATELLITE FOR ASTROMETRY AND PHOTOMETRY

We propose a small interferometer on a minisatellite, named DIVA (Deut sches Interferometer fur Vielkanalphotometrie und Astrometrie), to per form astrometric and photometric observations of at least one million stars. It would exceed the performance of Hipparcos in all important p arameters. With a possible launch in 2002 DIVA would provide for all s tars brighter than V = 10.(m)5 parallaxes better than 0.8 milliarcseco nds (mas) proper motions better than 2 mas/y broad-band photometry wit h a typical accuracy of 0.002 mag multi-channel intermediate-band phot ometry with a typical accuracy of 0.01 to 0.02 mag For the 100 000 sta rs observed by Hipparcos, proper motions with a typical accuracy of 0. 1 to 0.2 mas/y and parallaxes of 0.3 to 0.5 mas can be obtained in com bination with the Hipparcos results. The scientific potential of this mission and a possible layout of its optical system are described in t his paper.