Award Date
5-15-2026
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Physics and Astronomy
First Committee Member
Zhaohuan Zhu
Second Committee Member
Rebecca Martin
Third Committee Member
Jason Steffen
Fourth Committee Member
Pengtao Sun
Number of Pages
135
Abstract
Understanding planet formation requires linking the large-scale radiative heating of protoplanetary disks to the small-scale dust–gas instabilities that assemble planetesimals. To model the thermal structure that governs where solids survive, how turbulence behaves, and which chemical pathways operate, we developed a new framework in the open-source radiation-hydrodynamics code Athena++, incorporating frequency-dependent dust absorption and scattering opacities and introducing radial rays that self-consistently capture stellar irradiation. Comparisons between hydrostatic disk models and Monte Carlo radiative-transfer benchmarks show that multigroup treatments with only three frequency bands reproduce equilibrium temperatures to within roughly 10% while lowering computational cost by an order of magnitude, enabling efficient modeling of irradiated disks across a wide range of optical depths and resolving the vertical temperature gradients that shape disk dynamics and volatile chemistry. Because these thermal structures control the onset of dust–gas instabilities, we also conduct the first controlled comparison of the streaming instability across seven hydrodynamic codes, spanning finite-volume and finite-difference methods and treating dust either as Lagrangian particles or as a pressureless fluid. While all codes agree on the qualitative progression from exponential growth to filament formation and turbulent saturation, dust-modeling choices introduce the largest quantitative differences at moderate resolution, with particle-based approaches producing higher peak densities and broader high-density tails; these differences diminish at higher resolution, where saturated-state statistics converge. Together, these studies connect radiative heating and local dust dynamics, providing a unified theoretical framework for interpreting multiwavelength observations from JWST and ALMA that probe disk chemistry, temperature structure, and dust–gas substructure.
Keywords
Code comparison; Pebble accretion; Planetesimal formation; Radial drift; Synthetic observations; Vertical shear instability
Disciplines
Astrophysics and Astronomy | Other Physics | Physics
File Format
File Size
8300 KB
Degree Grantor
University of Nevada, Las Vegas
Language
English
Repository Citation
Baronett, Stanley Antedio, "From Dust to Planets: Dust–Gas Dynamics and Radiation Transport in Protoplanetary Disks" (2026). UNLV Theses, Dissertations, Professional Papers, and Capstones. 5503.
https://oasis.library.unlv.edu/thesesdissertations/5503
Rights
IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/