Origins of Spin-Orbit Misalignments in Extrasolar Planetary Systems

California Institute Of Technology, Pasadena CA

Investigators

Abstract

The earliest searches for extrasolar planets uncovered an unexpected class of giant planets that orbit twenty times closer to their host stars than the Earth does to the Sun. Just how these planets came to orbit so close to their host star has become even more perplexing, as recent observations have shown that some of these planets orbit in direction that does not correspond with the star's spin, unlike planets in our solar system. The PI will conduct a comprehensive theoretical study of the key physical processes that act to sculpt planetary systems, including our own. This project will provide a strong basis for the training of a graduate student. The PI will also mentor high school students through Caltech's "summer research connection" program. This theoretical/computational investigation will focus on reconciling smooth nebular-driven migration of giant planets and large spin-orbit misalignments through the disk-torquing mechanism. The effects of dynamical evolution within multiple star systems on the large-scale structure of the planet-forming disks will be examined, and the possibility of chaotic evolution of stellar spin axes will be quantified. The dependence of the misalignment amplitude on the specific modes of magnetic and gravitational disk-star coupling will be critically analyzed, with an eye towards explaining the observed correlation between orbital obliquity and stellar effective temperature.