According to both spectroscopic measurements and interior models, Jupiter, Saturn, Uranus and Neptune possess gaseous envelopes that are enriched in heavy elements compared to the Sun. Straightforward application of the dominant theories of gas giant formation - core accretion and gravitational instability - fail to provide the observed enrichment, suggesting that the surplus heavy elements were somehow dumped onto the planets after the envelopes were already in existence. Previous work has shown that if giant planets rapidly reached their cur rent configuration and radii, they do not accrete the remaining planetesimals efficiently enough to explain their observed heavy-element surplus. We ex plore the likely scenario that the effective accretion cross-sections of the giants were enhanced by the presence of the massive circumplanetary disks out of which their regular satellite systems formed. Perhaps surprisingly, we find that a simple model with protosatellite disks around Jupiter and Saturn can meet known constraints without tuning any parameters. Fur thermore, we show that the heavy-element budgets in Jupiter and Saturn can be matched slightly better if Saturn’s envelope (and disk) are formed roughly 0.1 — 10 Myr after that of Jupiter. We also show that giant planets forming in an initially-compact con figuration can acquire the observed enrichments if they are surrounded by similar protosatellite disks. Protosatellite disks efficiently increase the capture cross-section, and thus the metallicity, of the giant planets. Detailed models of planet formation must therefore account for the presence of such disks during the early stages of solar system formation.

Planet migration is an important part of the formation of planetary systems, both in the Solar system and in extrasolar systems. When a planet scatters nearby comet- and asteroid-size bodies called planetesimals, a significant angular momentum exchange can occur, enough to cause a rapid, self-sustained migration (change of semi-major axis) of the planet. This migration has been studied for the particular case of the four outer planets of the Solar System, but is not well understood in general. This thesis used the Miranda computer simulation code to perform a broad parameter-space survey of the physical variables that determine the migration of a single planet in a planetesimal disk. A simple model presented within matched well with the dependencies of the migration rate for low-mass planets in relatively high-mass disks. When the planet's mass exceeded that of the planetesimals within a few Hill radii, the migration rate decreased strongly with planet mass. Other trends were identified with the root-mean-squared eccentricity of the planetesimal disk, the mass of the particles dragged by the planet in the corotation region, and the index of the surface density power law. The issue of resolution was also addressed, and it was shown that many previous works in this field may have suffered from being under-resolved. The trends were discussed in the context of an analysis of the scattering process itself, which was performed using a large simulation of massless planetesimals. In particular, a bias in scattering timescales on either side of the planet's orbit leads to a very strong tendency for the planet to migrate inwards, instead of outwards. The results of this work show that planet migration driven by planetesimal scattering should be a widespread phenomenon, especially for low-mass planets such as still-forming protoplanets. The simple model provided here, augmented by many more subtle effects, will prove essential to any future work in this underestimated field. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2007-09-09 14:28:46.501

Thesis (M.S.)--University of Hawaii at Manoa, 2008. / Includes bibliographical references (leaves 208-234). / xiv, 234 leaves, bound ill. (some col.) 29 cm

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 6 uppsatser.

Report (M. Eng.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 75-76). Also available via the Internet.

Thesis--University of Florida. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 204-208).

Diss. phil.-hist. Univ. Bern, 2002. / Sowohl in gedruckter Form wie auf CD-ROM vorhanden.

Thesis--University of Florida. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 195-199).

Kiel, Univ., Diss., 2000. / Computerdatei im Fernzugriff.

Köln, University, Diss., 2004.