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The Orbital Evolution of Extrasolar Planets After Formation

TitleThe Orbital Evolution of Extrasolar Planets After Formation
Publication TypeThesis
Year of Publication2007
AuthorsVeras, DG

Our knowledge of the dynamical evolution of extrasolar planets around Solar-type stars relies on only one decade of sparse data. Theoretical models must be invoked in order to help explain the data and project where and when data should be obtained in the future. Such models rely analytically on sometimes centuries-old celestial mechanics and numerically on the latest fastest computers and clever integration algorithms. This thesis utilizes both analytical and numerical approaches in order to create such models, and is constructed from an enhanced rearrangement of refereed work and in-progress studies.

Chapter 1 provides the context for the approaches taken and studies performed in later chapters. I present a current snapshot of the known 200+ extrasolar planets with a discussion of their orbital properties and correlations, and discuss the highly relevant intertwined dynamical topics of "resonances" and disk planet interactions. Resonances have been shown to sculpt the architecture of the Solar System, and likely influence the formation and subsequent evolution of extrasolar systems. Large-scale disk-planet interactions may also play a pivotal role in determining the final dynamical state of an exosystem.

Chapters 2-4 semianalytically treat the motions of multi-planet exosystems through their resonant and secular dynamics through comparison with dynamical models of the Solar System. Chapter 2 details the general resonant integrator I have constructed and applies the integrator to a resonant multi-planet system of interest, and Chapter 3 applies the integrator to small body Solar System problems with an eye towards extrapolating to as-yet-unseen analogs in exosystems. Chapter 4 generalizes Laplace-Lagrange secular theory to fourth-order and applies the expanded theory to the applicable exosystems.

Chapters 5-8 detail numerical gravitational scattering experiments amongst multiple extrasolar planets of various relevant configurations. Chapter 5 illustrates statistically the prevalence of outward migration in extrasolar planetary systems, and Chapter 6 explores the stability of planets on significantly inclined orbits, a topic of increasing interest as more exoplanetary inclinations are deduced. Chapters 7 and 8 showcase the link between terrestrial and giant planets in the same system.

Chapter 9 provides a concise summary, and the appendices contain relevant unrefereed material. Appendix A provides analytical formulations of the evolution of accretion disk surface density proles, and Appendix B espouses the speculative but realistic prospects for exoplanets existing in an exotic cataclysmic variable environment.