EXTRASOLAR PLANET DETECTION AT INFRARED WAVELENGTHS FROM THE EARTH

We show that extrasolar planets in orbit around nearby stars can be de tected from the ground or from a stratospheric telescope in the infrar ed region of the spectrum. We present calculations on the detectabilit y of extrasolar planets, using Erich Grossman's Atmospheric Transmissi on (AT) code to compute atmospheric transmission at bands centered at 11 mu m, 20 mu m, 27 mu m, 200 mu m, 225 mu m, 350 mu m, 450 mu m, 640 mu m, 750 mu m, and 870 mu m. Detection limits for terrestrial and Jo vian planets orbiting Sun-like stars are presented by assuming Planck emission. We consider several potential sites including the south pole , a 5000-m elevation site in the Atacama Desert in Chile, Mauna Kea in Hawaii, and an aerostat-borne telescope flown near the poles. We cons ider extrasolar planet detection with a 10-m class mid-IR telescope an d a dilute aperture stratospheric telescope consisting of 4-m mirrors optimized for this task. Detection in the submillimeter, even with a 1 0(4) m2 collecting area array is extremely difficult because of low at mospheric transparency, and the decrease (proportional to lambda(-2)) in planet emission with increasing wavelength in the Rayleigh-Jeans li mit. We discuss critical technologies needed for this undertaking, inc luding tethered aerostats and balloon-borne telescopes, the developmen t of mid-IR nulling interferometry, actively cooled optics operating i n the atmosphere, and optimized filters that are matched to the atmosp heric transmission windows.