Illuminating Protoplanetary Disk sub-Structures and their Indirect Effects on Exoplanets
Bibliographic record
Abstract
Of all the areas of astrophysics, the scales involved in forming planets span the most orders of magnitude. One of the biggest outstanding questions in astrophysics is how planet formation proceeds. Everything from sub-micron sized dust grains that are responsible for passively heating a protoplanetary disk, to centimeter sized pebbles which accrete to form planets, or gaps and rings in protoplanetary disks that are tens of AU in diameter, can effect the planets that eventually form. In this thesis, I will describe several contributions to this enormous field which all attempt to understand the substructures in protoplanerary disks and how they affect planet formation. I begin by focusing on a particular variety of exoplanet called super-Earths or sub-Neptunes. I investigate the relationships between planet properties and their host star (as a proxy for the conditions in the protoplanerary disk) and compare the observed trends with those implied or predicted by various theories of planet formation. Then I re-focus onto the protoplanetary disk by performing a linear perturbation of the secular gravitational instability with drifting dust. Previous analytical derivations of growth rates do not include the radial drift of dust, which is a guarantee in protoplanetary disks. I show that not only does the instability persist, but also the radial dust drift excites larger scale perturbations than disks with non-drifting dust. Lastly, I perform 2D hydrodynamic simulations of irradiated protoplanetary disks. My simulations capture the growth of the irradiation instability and the inward propagating thermal waves that are predicted by linear theory. Interestingly, I find that the thermal waves stall and the disk reaches a steady state. Such a steady state produces sub-structure in scattered light and thermal continuum emission on scales that are, unfortunately, below current detection thresholds. Together, these works expand our knowledge and understanding of protoplanetary disk substructures and their implied affects on the resulting planetary systems. They also introduce a novel steady state of protoplanetary disks which has far reaching consequences. Protoplanetary disks set the stage for planet formation and the work presented in this thesis paves the way for further investigation of irradiated protoplanetary disks and the implied imprints left on the exoplanets that eventually form.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".