Anatomy of a fall: stationary and super-Keplerian spiral arms generated by accretion streamers in protostellar discs
Bibliographic record
Abstract
ABSTRACT Late-stage infall onto evolved protoplanetary discs is an important source of material and angular momentum replenishment and disc substructures. In this paper, we used 3D smoothed particle hydrodynamics simulations to model streamer–disc interactions for a prograde streamer. The initially parabolic streamer interacts with the disc material to excite disc eccentricity, which can last on the order of $10^5$ yr. We found that the spiral arms the streamer excited in the disc can have a variety of pattern speeds, ranging from stationary to super-Keplerian. Spiral arms with various pattern speeds can exist simultaneously, providing a way to diagnose them in observations. Streamer-induced spirals appear similar to those generated by a massive outer companion, where the pitch angle of the spiral increases towards the source of the perturbation. Additionally, the spiral arms can show large and sudden pitch angle changes. Streamer-induced spirals are long-lived, lasting approximately $3\!-\!4$ times longer than the initial streamer infall time-scale (${\sim} 10^4$ yr). After the initial interaction with the disc, a long-lasting low m azimuthal mode persists in the disc.
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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 | 0.000 |
| 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 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".