The Evolution of Circumstellar Disks

Open Access
Richert, Alexander John Wolf
Graduate Program:
Astronomy and Astrophysics
Doctor of Philosophy
Document Type:
Date of Defense:
September 08, 2017
Committee Members:
  • Eric D Feigelson, Dissertation Advisor/Co-Advisor
  • Eric D Feigelson, Committee Chair/Co-Chair
  • Kevin Luhman, Committee Member
  • Steinn Sigurdsson, Committee Member
  • Reka Z Albert, Outside Member
  • Eric B Ford, Committee Member
  • Marc Kuchner, Committee Member
  • planet formation
  • circumstellar disks
  • astrophysics
  • hydrodynamics
Angular momentum conservation during protostellar collapse leads to long-lived, gas-rich circumstellar disks where planets form through the concentration of gas and dust by one or both of gravitational agglomeration and aerodynamic concentration of dust. In this dissertation, I summarize four projects aimed at understanding the evolution of planet-forming disks and the debris-dominated disks that remain after the primordial gas has been depleted. The first two projects make use of X-ray and near-infrared point source data to explore the longevity of young circumstellar disks, providing constraints on the timescales available for planet formation; the first is a study of disk depletion rates in 69 young stellar clusters, while the second examines the role of external photoevaporation by massive stars in accelerating disk depletion. Next, I discuss numerical simulations of planet--disk interactions in gas-rich, optically thick disks, with implications for the observability of newly-formed massive planets. Lastly, I present numerical simulations of gas--dust interactions in optically thin disks in order to explore their effect on disk morphology, with potential consequences for identifying embedded planets.