DARWIN FRINGE SENSOR (DWARF): CONCEPT STUDY

摘要

The DarWin AstRonomical Fringe sensor (DWARF) is one of the most critical components of DARWIN. DWARF's main goal is to measure all the optical path differences from the observed star down to the detector, induced by relative displacements of the 7 free flyers, by vibrations or by thermal effects, in order to enable their correction by delay lines. In the current error budget, nanometric accuracies are required to reach a sufficient null. DWARF must also measure tip/tilt, defocus, astigmatism and coma. The goal of the study presented here is to identify the best concept for DWARF within the DARWIN environment. Main issues are the selection of the spectral domain from the target list, the merging of a wavefront sensor and an interferometer taking into account the number of beams, the acquisition procedure and space constraints. This leads to a simple and innovative concept. A preliminary DWARF performance is estimated by simulation. In addition, a laboratory breadboard will be manufactured in order to test experimentally the most critical points, as detailed in another paper of this conference "DARWIN fringe sensor (DWARF): breadboard development" by E. Schmidt et al.