Tandem Planetary Formation Theory

Discs and Planetary Formation

The formation, structure and evolution of protoplanetary discs is considered. The formation of giant planets within the environment of these models is also discussed.

Metallicity, planetary formation and migration

Recent observations show a clear correlation between the probability of hosting a planet and the metallicity of the parent star. Since radial velocity surveys are biased, however, towards detecting planets with short orbital periods, the probabilitymetallicity correlation could merely reflect a dependence of migration rates on metallicity. We investigated the possibility, but find no basis to s...

Brown and Shook — Planetary Theory

The formation of globules in planetary nebulae

We discuss the formation of globules in planetary nebulae, typified by those observed in the Helix Nebula. We show that the properties of the globules, their number, mass, separation, and overall geometry strongly support a scenario in which globules are formed by the fragmentation of a swept-up shell as opposed to models in which the knots form in the AGB wind. We show that the RT or other ins...

The formation of bipolar planetary nebulae

Using a radiation-hydrodynamics code I follow the formation of planetary nebulae around stars of different mass. Because a more massive central star evolves much faster than a lower mass one, it is to be expected that this will affect the formation of the PN. For the stars I use the evolutionary tracks for remnants with masses of 0.605 M⊙ and 0.836 M⊙, taken from Blöcker (1995). The AGB wind is...