title: Evidence for dust grain growth in young circumstellar disks.
abstract: Hundreds of circumstellar disks in the Orion nebula are being rapidly destroyed by the intense ultraviolet radiation produced by nearby bright stars. These young, million-year-old disks may not survive long enough to form planetary systems. Nevertheless, the first stage of planet formation-the growth of dust grains into larger particles-may have begun in these systems. Observational evidence for these large particles in Orion's disks is presented. A model of grain evolution in externally irradiated protoplanetary disks is developed and predicts rapid particle size evolution and sharp outer disk boundaries. We discuss implications for the formation rates of planetary systems.
authors.affiliation: Laboratory for Atmospheric and Planetary Sciences, University of Colorado, Boulder, CO 80309-0392, USA. throop@boulder.swri.edu
authors.forename: H B
authors.initials: HB
authors.lastname: Throop
authors.forename: J
authors.initials: J
authors.lastname: Bally
authors.forename: L W
authors.initials: LW
authors.lastname: Esposito
authors.forename: M J
authors.initials: MJ
authors.lastname: McCaughrean
mesh_terms: D055580:Astronomical Phenomena; D001256:Astronomy; D019443:Cosmic Dust; D019419:Evolution, Planetary
chemical_list: D019443:Cosmic Dust