Collisional Consequences of Big Interstellar Grains
E. Grün, M. Landgraf (MPI für Kernphysik Heidelberg)
Identification by Ulysses of interstellar grains inside the planetary
system provides new window for study of the local interstellar medium.
Dust particles found by Ulysses and confirmed by Galileo are bigger
( ) than the typical interstellar grains
( ). Recently even bigger (about ) interstellar
meteors have been identified (Taylor et al., Nature, 380, 323,
1996). The goal of this analysis is the investigation of collisional
effects of big interstellar grains. Interstellar dust is
conventionally described by the MRN size distribution (Mathis, Rumpl
and Nordsieck, ApJ, 217, 105, 1977) ranging from 5 to in
size (about to ). On the basis of this size
distribution Jones et al. (ApJ, 469, 740, 1996) find that collisional
shattering is a source of the smallest of these grains, but grains
bigger than about are rapidly depleted. In this study it is
investigated whether collisions with the newly found bigger particles
could provide a source for the classic interstellar grains, thereby,
solving the mystery of the rapid destruction times of interstellar
grains compared to the transport and injection times of grains into
the diffuse interstellar medium.