Presentation #206.12 in the session New Mission Concepts — iPoster Session.
Direct studies of ultracool atmospheres are a key window into the properties, formation, and evolution of gas-giant exoplanets. In this arena, the variability of integrated light from exoplanets is a powerful diagnostic, as light curves provide two-dimensional spatial information about their heterogeneous photospheres and multi-wavelength light curves probe the third spatial dimension of atmospheric depth. Such variability ultimately arises from exoplanet weather, i.e., latitudinal, longitudinal, and vertical changes in emitted light, whose observable signal is modulated by the exoplanet’s rotation.
While “exometeorology” studies of directly imaged exoplanets have been too challenging for current telescopes, such studies have used free-floating planets and brown dwarfs as valuable analogs. Extensive ground- and space-based studies have found brightness variations of 1-20% over timescales of hours and days. But very little is known about the longer-term behavior of such variability, since nearly all previous work has been limited by earth’s day-night cycle, telluric absorption, and the lack of telescope resources for continuous observations.
SUWIE (Substellar Weather Infrared Explorer) is a 6U cubesat concept to observe a sample of free-floating exoplanets and brown dwarfs for a period of up to a year. The spacecraft design is based on the Hyperspectral Thermal Imager, another NASA-funded 6U platform being developed at the Hawaii Space Flight Lab. The camera payload will use a linear-mode avalanche photodiode (LmAPD) array, a low-noise, high-sensitivity infrared detector. In addition to the scientific goals outlined above, SUWIE will raise the readiness level of this compelling detector technology, which is a prime candidate for future exoplanet direct imaging and spectroscopy missions.