Abstract
This work investigated the link between exceptionally bright and variable debris disks, often called extreme debris disks, and energetic collisions between planetary embryos - giant impacts. The primary method of investigation was a simulation pipeline which modelled the evolution of the disk created by dust material ejected by a giant impact. This pipeline included an $N$-body code which simulated the dynamical evolution of the dust, a semi-analytical Poynting-Robertson (P-R) model which approximated the effect of P-R drag on the mass distribution of the disk, and a radiative transfer package to reproduce the infrared emission of the dust in the disk. Eighty four collision scenarios were run, covering a broad parameter space. The collision parameters included the eccentricity of the centre of mass of the two colliders, the position of the collision along this orbit, and the orientation of the collision with respect to the same orbit.A detailed analysis of the patterns in disk morphology and infrared emission was performed to determine how observability changed in different cases. Eccentric disks were found to inherit the eccentric properties of their centre of mass progenitor orbit. The orientation of the collision with the respect to this orbit helped to determine how closely the disk resembled the centre of mass orbit. Some orientations resulted in disks more tightly concentrated around the original orbit while others were more distributed. Additionally, increased eccentricity created more distinct variability in disk emission owing to changes in dust temperature, but also suppressed the formation of certain short-term variations dependent on collision position. Observed short-term variability is consistent with the variability seen in some of the simulations, lending support for the hypothesis that giant impacts are the source of extreme debris disks. Poynting-Robertson drag was found to have a minimal effect on the disk over timescales of around twenty orbits.
| Date of Award | 21 Mar 2023 |
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| Original language | English |
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| Supervisor | Zoe M Leinhardt (Supervisor) & Hannah R Wakeford (Supervisor) |