Interstellar Grains in the Solar System

It is likely that presolar interstellar grains are preserved inside comets and asteroids. If these particles can be collected, identified and properly analyzed in the laboratory, they could provide a vital link between the study of the early solar system and the interstellar materials that preceded it. Abundant isotopic evidence from meteorites indicates that interstellar components have survived in asteroids although it is not evident that unaltered individual grains survived. Continued work on meteorites, interplanetary dust and samples directly retrieved from comets will likely lead to new insight into interstellar and circumstellar grain properties and processes and provide constraints on grain models.