Spatially resolving the accretion shocks on the rapidly-rotatingM0 T-Tauri star MN Lupi
Bibliographic record
Abstract
We obtained high-resolution, high-quality VLT/UVES spectra to reconstruct the two-dimensional surface structure of the rapidly-rotating classical T-Tauri star MN Lupi on two separate nights. Both surface maps show a structured warm (5000 K) band centered around the pole at a latitude of ≈65°. Located within the band are two hot spots with temperatures of approximately or possibly even in excess of 5800 K, i.e. 2000 K above the effective photospheric temperature. Both maps appear with an adjacent equatorial band of temperature 3400 K, some 400-500 K below the effective photospheric temperature. While we interpret the two hot spots and the warm high-latitude band to be the heating points from two accretion impacts at the time of our observations and their redistributed energy trailed due to the fast stellar rotation, respectively, the cool equatorial band may not be cool after all but due to obscuration of the stellar surface by the innermost region of the disk. The fact that the hot spots appear at high stellar latitude is in agreement with the magnetospheric accretion model that proposes material funnelling onto the star along a predominantly dipolar magnetic field at roughly 50° latitude. The evidence of ongoing disk accretion, together with the very fast rotation of MN Lupi of just 3-4 times below its break-up velocity, suggests that the accretion mechanism is the cause of its rapid surface rotation. We present a model of magnetic star-disk coupling for MN Lupi that predicts a polar surface magnetic field of ≈3 kG.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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".