Theoretical Limits on Extrasolar Terrestrial Planet Detection with Coronagraphs

摘要: Many high-contrast coronagraph designs have recently been proposed. In this paper, their suitability for direct imaging of extrasolar terrestrial planets is reviewed. We also develop a linear algebra based model coronagraphy that can both explain the behavior existing coronagraphs and quantify coronagraphic performance limit imposed by fundamental physics. find maximum theoretical throughput equal to 1 minus nonaberrated noncoronagraphic PSF telescope. describe how reaching may be designed, much improvement over best design still possible. Both analytical numerical simulations show rapidly degrades as source size increased: "highest performance" coronagraphs, those with highest smallest inner working angle (IWA), are most sensitive stellar angular diameter. This unfortunately rules out possibility using small IWA (<λ/d) planet mission. Finally, detailed simulation accurately accounts size, zodiacal exozodiacal light used efficiency in possible real observing program. photon noise-limited regime, 4 m telescope theoretically optimal able detect Earth-like around 50 stars hr exposure time per target (assuming 25% exozodi levels similar our solar system). at least two approach level ideal monochromatic case considered study.