title: Clearing of the Protosolar Nebula: Constraints from meteorites, asteroids, and planets

authors: Shogo Tachibana

abstract: Circumstellar disks are a natural outcome of the star formation process and the sites where planets form. Gas, mainly hydrogen and helium, accounts for about 99% of the disk's initial mass while dust, in the form of submicron- sized grains, only for about 1%. In the process of forming planets circumstellar disks disperse: sub-micron dust grains collide and stick together to form larger aggregates; gas accretes onto the star, onto the cores of giant and icy planets, and evaporates from the disk surface. A key question in planet formation is the timescale and physical mechanism for the clearing of protoplanetary disks. How rapidly gas and dust disperse determines what type of planets can form.

In my talk, I compare the evolution of protoplanetary disks to that of the protosolar nebula. I seek constraints on the clearing of gas and dust in the protosolar nebula from the properties of meteorites, asteroids, and planets. Finally, we try to anchor the evolution of protoplanetary disks to the Solar System chronology and discuss what observations and experiments are needed to understand how common is the history of the Solar System.