Small icy bodies in the inner Solar System

Small icy bodies in the inner solar system, particularly the Asteroid “Main” Belt, offer a unique platform for testing various Solar System formation models by providing clues of the early physical and chemical conditions in the primary disk. Despite theoretically being more likely to be located in the outer Asteroid Belt, icy bodies are widely distributed across the inner Solar System and show a variety of compositions, orbital properties, and levels of activity. This is mainly because their small sizes and irregular shapes increase the likelihood of their drifting from their points of origin due to both gravitational and nongravitational effects. Collectively, these processes lead to the migration of small bodies from as far as the Trans-Neptunian region to the inner Solar System, including the Near-Earth environment, and may have been an essential pathway in the delivery of water and volatiles to Earth. The resulting long-term evolution of their orbital properties complicates the synthesis of knowledge that can be acquired from studying small icy bodies. However, ongoing and future space exploration missions, increased Earth-based observation density and accuracy, and continuously improving simulations are going to result in a better characterization of the distribution of ice in the inner solar system and more accurate models of the planetary system’s formation.