SPICA coronagraph instrument: Characterization of atmospheres and physical parameters of giant planets by direct imaging and spectroscopy

We present the current status of the development of the SPICA Coronagraph Instrument (SCI). SPICA is a nextgeneration 3-meter class infrared telescope, which will be launched in 2022. SCI is high-contrast imaging, spectroscopic instrument mainly for direct detection and spectroscopy of extra-solar planets in the near-to-mid infrared wavelengths to characterize their atmospheres, physical parameters and evolutionary scenarios. SCI is now under the international review process. In this paper, we present a science case of SCI. The main targets of SCI, not only for direct imaging but also for spectroscopy, are young to matured giant planets. We will also show that some of known exoplanets by groundbased direct detection are good targets for SCI, and a number of direct detection planets that are suitable for SCI will be significantly increased in the next decade. Second, a general design of SCI and a key technology including a new highthroughput binary mask coronagraph, will be presented. Furthermore, we will show that SCI is potentially capable of achieving 10^-6 contrast by a PSF subtraction method, even with a telescope pointing error. This contrast enhancement will be important to characterize low-mass and cool planets.