Gap formation and stability in non-isothermal protoplanetary discs
Bibliographic record
Abstract
Several observations of transition discs show lopsided dust distributions. A potential explanation is the formation of a large-scale vortex acting as a dust-trap at the edge of a gap opened by a giant planet. Numerical models of gap-edge vortices have so far employed locally isothermal discs in which the temperature profile is held fixed, but the theory of this vortex-forming or ‘Rossby wave’ instability was originally developed for adiabatic discs. We generalize the study of planetary gap stability to non-isothermal discs using customized numerical simulations of disc–planet systems where the planet opens an unstable gap. We include in the energy equation a simple cooling function with cooling time-scale |$t_{\rm c}=\beta \Omega _{\rm k}^{-1}$|, where Ωk is the Keplerian frequency, and examine the effect of β on the stability of gap edges and vortex lifetimes. We find increasing β lowers the growth rate of non-axisymmetric perturbations, and the dominant azimuthal wavenumber m decreases. We find a quasi-steady state consisting of one large-scale, overdense vortex circulating the outer gap edge, typically lasting O(103) orbits. We find vortex lifetimes generally increase with the cooling time-scale tc up to an optimal value of tc ∼ 10 orbits, beyond which vortex lifetimes decrease. This non-monotonic dependence is qualitatively consistent with recent studies using strictly isothermal discs that vary the disc aspect ratio. The lifetime and observability of gap-edge vortices in protoplanetary discs is therefore dependent on disc thermodynamics.
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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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".