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Project Progress

In collaboration with Mayer, Quinn is exploring the viability of the gravitational instability model for the formation of gas giant planets. In collaboration with a number of workers in the field, the reliability of the numerical techniques used for modeling is being tested. With Mejia and Lufkin, they have conducted the first 3D SPH radiative transfer simulations of a massive protoplanetary disk. They have also used high resolution 3D SPH simulations to study the evolution of self-gravitating binary protoplanetary disks. They find that massive disks that fragment if considered in isolation develop only transient overdensities when part of a binary system with a separation of 60 AU. Tidally induced shocks heat the disk to above 200K, vaporizing water and making it difficult to form giant planets in any model. Mejia and Quinn are also investigating the evolution of solids as they interact with the gas in protoplanetary disks. While centimeter size bodies remain tightly coupled to the gas, meter size bodies settle very quickly and migrate to the spiral density enhancements.

Kaib along with Barnes and Raymond have simulated the formation of terrestrial planets in four systems with known giant planets under the assumption that the giant planet inventory is complete. If the giant planets formed and migrated quickly to their current orbits, then terrestrial planets may form from a second generation of planetesimals. They find that only the 55 Cancri system can form terrestrial planets in the habitable zone with substantial water in this scenario.

Kaib has been exploring the evolution of the Oort cloud, and the intensity of resulting comet showers under the assumption that the Solar System formed in a dense stellar environment. The stellar environment has a significant effect on the number of comets that end up in the Oort cloud, and therefore the intensity of comet showers.

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