The onset of planet formation in brown dwarf disks

The onset of planet formation in protoplanetary disks is marked by the growth and crystallization of sub-micrometer-sized dust grains accompanied by dust settling toward the disk mid-plane. Here, we present infrared spectra of disks around brown dwarfs and brown dwarf candidates. We show that all three processes occur in such cool disks in a way similar or identical to that in disks around low- and intermediate-mass stars. These results indicate that the onset of planet formation extends to disks around brown dwarfs, suggesting that planet formation is a robust process occurring in most young circumstellar disks.
Planet formation starts with the growth of submicrometer-sized amorphous grains in the protoplanetary disks [e.g., (1, 2)]. Theory predicts that larger grains settle faster to the disk mid-plane, resulting in [...]