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May 30, 2014: Evolution of circumstellar disks and planet formation

Posted on May 16, 2014 in Seminars

Wladimir Lyra (Caltech)

During the first million years of evolution, nascent planetary
systems are embedded in dense disk­-shaped clouds of gas. These
circumstellar disks are home to a myriad of hydrodynamical processes,
which bring about turbulence and the emergence of viscous­-like behavior,
enabling accretion of gas onto the protostar. Meanwhile, micron­size dust
grains embedded in the disk are growing through coagulation onto pebbles
and rocks. Turbulence has a positive effect on these small solids,
concentrating them into transient high pressure regions for long enough to
achieve gravitational collapse into km­-sized bodies, forming the first
planetesimals. Giant storm systems in the disk, similar to Jupiter’s Great
Red Spot, may exist in quiescent zones of the disk. These are even more
prone to collecting solid material, producing the first terrestrial
planets and cores of giant planets. In this talk I will discuss the state
of the art and recent advances in the field of planet formation, as well
as pressing problems such as the asymmetries observed in ALMA images of
circumstellar disks, and how to interpret them.