Probing Exoplanet Atmospheric Physics with the EXoplanet Climate Infrared TElescope (EXCITE)

We propose to build and fly the EXoplanet Infrared Climate TElescope (EXCITE). EXCITE is a low resolution 1-4 micron spectrograph that will measure spectroscopic phase curves of bright, short-period extrasolar giant planets, or hot Jupiters, over their full orbits. These spectral measurements probe varying depths in exoplanets atmospheres thus contributing to our understanding of general circulation models, which will provide key insights into atmospheric physics and chemistry. Hot Jupiters provide an ideal laboratory for understanding atmospheric dynamics, which is a stepping stone to understanding the foundation of models which will be needed to search for potentially habitable planets.

With its long observation times and special purpose design to characterize exoplanet atmospheres, EXCITE can deliver science that the James Webb Space Telescope (JWST) is unlikely to carry out, as well as complement the science which JWST will deliver. EXCITE uses a commercially available 0.5 m diameter telescope pointed with high accuracy and stability using the successful Balloon Imaging Testbed (BIT) pointing platform. The telescope is coupled to a cooled spectrometer made from commercially available components. EXCITE will flight test detector readout technology that will be used on the Wide Field Infrared Survey Telescope (WFIRST). The combination of these elements results in a unique instrument for exoplanet atmospheric characterization. EXCITE's initial science will result from an Antarctic long duration balloon flight.