HARDI-2: a high-angular-resolution deployable interferometer for UV observations of nearby stars

摘要

Abstract: We describe a concept for an orbiting astronomical observatory which will allow high spatial resolution far-UV observations of nearby stars. The scientific goal is to study stellar activity and mass loss using imaging and spectroscopy. Specific areas of study include stellar surfaces, large scale magnetohydroynamic effects, interacting binaries and stellar winds. The instrument is an interferometer with an 8-meter baseline providing 3 milliarcseconds resolution at 1200 Angstrom. The interferometer configuration is of the Fizeau type which affords excellent ultraviolet throughput because of the small number of reflections. The collecting aperture is composed of six 0.6 meter diameter elements distributed on a circle in such a way as lead to near uniform u-v plan coverage when the instrument is rotated around the line of sight. This will lead to excellent imaging capabilities. The interferometer individual channels are kept coaligned and coherent using the light of a nearby guide star. The supporting structure is folded for launch and automatically deployed once on orbit. To minimize disturbance torques and thermal shocks, the spacecraft will be located on a high earth orbit or at the Lagrangian point.!3