Vortragsdetails

Mittwoch, 23. Mai 2012 - 16:15

Paola Pinilla:

"Overcoming the meter-size barrier in planet formation theory"

Zusammenfassung. Planet formation via core accretion implies the growth from micron size particles to planetesimals. This process which covers more than forty orders of magnitude in mass, contains different physical challenges. Theoretically, the so-called "meter-size barrier" is caused when dust grows to meter sized objects at few AU (or millimeter sized pebbles in the outer regions of the disk) and due to their interaction with the gas, they drift towards the star on timescales shorter than 100 years. Moreover, the high relative velocities due to turbulence and radial drift cause fragmentation collisions. Nevertheless, radio observations of protoplanetary disks have revealed the presence of millimeter-size dust particles in the outer regions of disks unlike is expected by theory. We introduce how the presence of long-lived pressure bumps moderate the rapid inward drift using a disk model that includes dust coagulation and fragmentation. These pressure inhomogeneities allow the retainment of large dust particles on million years time scales, leading to a better agreement between observations and theory.