DISK MASSES IN THE EMBEDDED AND T TAURI PHASES OF STELLAR EVOLUTION
Bibliographic record
Abstract
Motivated by a growing concern that masses of circumstellar disks may have been systematically underestimated by conventional observational methods, we present a numerical hydrodynamics study of time-averaged disk masses (〈 M d 〉) around low-mass Class 0, Class I, and Class II objects. Mean disk masses ( ) are then calculated by weighting the time-averaged disk masses according to the corresponding stellar masses using a power-law weight function with a slope typical for the Kroupa initial mass function of stars. Two distinct types of disks are considered: self-gravitating disks, in which mass and angular momentum are redistributed exclusively by gravitational torques, and viscous disks, in which both the gravitational and viscous torques are at work. We find that self-gravitating disks have mean masses that are slowly increasing along the sequence of stellar evolution phases. More specifically, Class 0/I/II self-gravitating disks have mean masses , 0.10, and 0.12 M ☉ , respectively. Viscous disks have similar mean masses ( –0.11 M ☉ ) in the Class 0/I phases but almost a factor of 2 lower mean mass in the Class II phase ( ). In each evolution phase, time-averaged disk masses show a large scatter around the mean value. Our obtained mean disk masses are larger than those recently derived by Andrews & Williams and Brown et al., regardless of the physical mechanisms of mass transport in the disk. The difference is especially large for Class II disks, for which we find –0.12 M ☉ but Andrews & Williams report median masses of the order 3 × 10 −3 M ☉ . When Class 0/I/II systems are considered altogether, a least-squares best fit yields the following relation between the time-averaged disk and stellar masses, 〈 M d 〉 = (0.2 ± 0.05)〈 M * 〉 1.3±0.15 . The dependence of 〈 M d 〉 on 〈 M * 〉 becomes progressively steeper along the sequence of stellar evolution phases, with exponents 0.7 ± 0.2, 1.3 ± 0.15, and 2.2 ± 0.2 for Class 0, Class I, and Class II systems, respectively.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".