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Solar System Research at STScI

Characterizing the small-body population of the solar system, shedding light on its origin and evolution.

Trans-Neptunian Region

STScI researchers use a wide range of multiwavelength observations to characterize objects in the trans-Neptunian region, including Kuiper belt objects, dwarf planets, and their satellites. These studies are based on extensive HST, Spitzer, and Herschel programs and, in the case of the Pluto system, on New Horizons data. The latter have led to breakthrough discoveries regarding Pluto's surface and its atmosphere that have changed our view of the dwarf planets. HST programs have also been used to support the New Horizons Pluto program and has led to the discovery of 4 new moons. The Kuiper Belt is a remnant of the primordial planetesimal population of the solar system and its study, and that of the dust produced in that region, offer important clues to interpret circumstellar disk observations, helping constrain planet and planetesimal formation models, and shedding light on the global architecture of extrasolar planetary systems.


Research programs at STScI, using mainly HST and ground-based facilities, have focused on studying the origin and evolution of active asteroids, to understand their disruption events and the nature of the main-belt comets. These studies have changed our understanding of which might have been the main contributors of water to early Earth. Other HST programs have focused on Ceres and Vesta in support of the Dawn mission. Also focus of investigation has been the zodiacal dust through polarimetry observations that help interpret those of extrasolar debris disks.


Using HST and ground-based facilities, STScI researchers have studied the origin and evolution of new comets. This has led to breakthrough discoveries that have resulted, for example, in the identification of the most primitive comet ever seen. Another research program focuses on interpreting the first interstellar comet ever detected to shed light on its origin.

Giant Planet Satellites

Using HST observations, STScI researchers have discovered of water plumes on Europa and have studied plume activity on Enceladus. Other research programs include the characterization of the outer planet's satellites, accretion and fragmentation processes in planetary rings, and the study of the scattering phase function of Saturn's G and D rings to aid at the interpretation of nearby debris disks.