Summary for the SPICA coronagraph instrument (SCI)

This paper is a summary of the SPICA Coronagraph Instrument (SCI) based on a review of previously published literature. The SCI is proposed for SPICA for the purpose of studying small-scale structures surrounding bright stars and galactic nuclei, which specifically include exoplanets (not only detection but also characterization of the atmosphere), protoplanetary and debris disks, dusty tori in active galactic nuclei, and interstellar matter around bright small-scale structures. High contrast images are produced in the SCI by using binary pupil-mask coronagraphs together with an image subtraction technique. The SCI is designed to have both the function of imaging (1’ x 1’field of view) and spectroscopic capability (R=200). The SCI possesses the capability of low-background spectroscopic coronagraphy over the continuous wavelength range from 4 to 28 micron. These specifications make the SCI a unique instrument for observations over a high dynamic range in the 2020s. After years of review in Japan and international review, the design of the instrument has been modified and simplified to reflect the scientific requirements. The SCI presently has neither a short channel nor a deformable mirror, both of which were present in the previous design.