The case for stochastic orbital migration in proto-planetary disks and Saturn’s rings

Many of the 869 known extra-solar planets are in multi-planetary systems.  These systems are the most interesting ones to study because they allow us to place tight constraints on planet formation. The protoplanetary disk in which planets form is turbulent and therefore stochastic forces are exerted onto embedded proto-planets. I will discuss formation scenarios for several systems that show strong evidence for such a phase of stochastic migration.  I will then present the first results from a new method which can simulate the formation history of an entire ensemble of planetary systems such as those discovered by Kepler. The results are once again consistent with the idea of stochastic migration.

There is only one place in the universe where we can directly observe the interaction of an astrophysical disk with an embedded body. This place is Saturn’s rings. Very high resolution images made by the Cassini Spacecraft reveal that small moons, so called moonlets or propellers, are changing their orbital parameters because of this interaction. The interaction is not smooth. Similar to the protoplanetary disk, Saturn’s rings are also turbulent. This is the first direct observation of orbital migration of an embedded object. Once again, I will show that it is perfectly consistent with the idea of stochastic migration.

If there is time, I will talk about a new community project, the Open Exoplanet Catalogue. Catalogues of stars and other astronomical objects are as old as astronomy itself. It is time for a dramatically new approach to managing astronomical databases. My idea borrows both the philosophy and tools from the open source community. I will show how one can use the version control system git and human-readable xml files to construct a catalogue of all discovered extrasolar planets. It is completely open and distributed. It allows everyone to correct errors and contribute new data.

MP 203

Hanno Rein (IAS/ Princeton)

March 28, 2013
13:00 - 14:00