The Fourier-Kelvin Stellar Interferometer: Exploring Exoplanetary Systems with an Infrared Probe-class Mission

We report results of a recent engineering study of an enhanced version of the Fourier-Kelvin Stellar Interferometer (FKSI) that includes 1-m diameter primary mirrors, a 20-m baseline, a sun shield with a ±45° Field-of-Regard (FoR), and 40K operating temperature. The enhanced FKSI is a two-element nulling interferometer operating in the mid-infrared (e.g. ∼ 5-15 μm) designed to measure exozodiacal debris disks around nearby stars with a sensitivity better than one solar system zodi (SSZ) and to characterize the atmospheres of a large sample of known exoplanets. The modifications to the original FKSI design also allows observations of the atmospheres of many super-Earths and a few Earth twins using a combination of spatial modulation and spectral analysis.