The Formation and Early Evolution of Binaries and their Environments
Author
Smullen, Rachel AnnIssue Date
2020Advisor
Kratter, Kaitlin M.
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The University of Arizona.Rights
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction, presentation (such as public display or performance) of protected items is prohibited except with permission of the author.Abstract
Binaries—two bodies of comparable mass that orbit a common center—influence the evolution of gas and planets in their vicinity and are ubiquitous in star and planet formation. And yet, because of the complexity binaries add to already complex problems, they have often been excluded from consideration in theoretical and observational work. In this dissertation, I present an exploration of the formation and early evolution of binaries and their environments in four contexts: debris in the Pluto-Charon system, dynamics in the Kuiper Belt of our Solar System, planetary systems around binary stars, and variability in star-forming cores. First, I explore the fate of debris that could have resulted from the giant impact origin of the Pluto-Charon dwarf planet binary to look for observational signatures of its formation that may persist to this day. Using N-body simulations, I estimate the cratering rates on Charon's surface that would result from collisions of small debris from the post-formation debris disk, and I also make predictions for the presence of a Pluto-Charon disk collisional family of debris that were ejected from the binary that may still be orbiting in the Kuiper Belt today. Second, I develop a machine learning algorithm to quickly and accurately classify the dynamical population membership of observed Kuiper Belt objects. Current classification methodologies require substantial human intervention, and with imminent surveys expected to increase the number of known Kuiper Belt objects by an order of magnitude, automated methods are required. I find good accuracy in my method and characterize the reasons the algorithm can fail, including object rarity and the inherent ambiguity of classification in a time-dependent system. Third, I simulate the dynamical evolution of the planet populations around both single and binary stars to understand the influence of a close central binary on planetary system architecture. I find that a central binary only changes the planet loss mechanism: planets around a binary are much more likely to suffer a catastrophic interaction with the binary and be ejected from the system rather than undergoing a more gentle scattering that can lead to collisions. Instead, the system architecture is primarily driven by the most massive planet in the system regardless of the central object. Finally, I study the time evolution of dense, star-forming cores using magnetohydrodynamical simulations. I create an algorithm to link cores through time, and I find that the structures we identify can have large variability in extracted quantities (such as mass) in time despite the distributions of those quantities remaining stable. I postulate that a large fraction of the variability could come from the structure identification algorithms, which rely upon relative measures of structure that can change in time.Type
textElectronic Dissertation
Degree Name
Ph.D.Degree Level
doctoralDegree Program
Graduate CollegeAstronomy