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Sampling the Evolution of Solar System Cometoids


Zhang, Qicheng (2024) Sampling the Evolution of Solar System Cometoids. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/mjje-pc39.


Comets are commonly defined to be planetesimals visibly losing mass through volatile sublimation. In the solar system, such behavior characterizes but a brief stage in the overall evolution of these objects, as limited by their supply of accessible volatile materials and the often short dynamical lifetimes of orbits sufficiently near the Sun for said volatiles to actually volatilize. In this thesis, I explore the characteristics of several different types of ``cometoids''---planetesimals visibly exhibiting comet-like mass loss sometime in their recent past, present, or near future---in both the outer and inner solar system at different stages in their physical and dynamical evolution. I first use stellar occultations---or rather, the lack thereof detected---to constrain their abundance of kilometer-scale objects in the Kuiper Belt, from which many comets are sourced. I then evaluate how the optical brightness, color, and polarization of dust ejected by a classical, currently active comet changes when exposed to the space environment in order to probe the material properties of its nucleus. Finally, I investigate an otherwise ordinary but active asteroid to explore how intense solar heating as it passes very near the Sun can volatilize its rocky surface to produce bright sodium emission explaining its comet-like behavior.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:comets; minor planets
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Planetary Sciences
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Hallinan, Gregg W.
Thesis Committee:
  • Brown, Michael E. (chair)
  • de Kleer, Katherine R.
  • Knutson, Heather A.
  • Hallinan, Gregg W.
Defense Date:26 September 2023
Non-Caltech Author Email:qicheng (AT)
Record Number:CaltechTHESIS:01012024-070706394
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for Chapter 2 adapted for Chapter 3 adapted for Chapter 4
Zhang, Qicheng0000-0002-6702-191X
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16271
Deposited By: Qicheng Zhang
Deposited On:04 Jan 2024 18:18
Last Modified:16 Jan 2024 23:50

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