The frequency of accretion disks around single stars: Chamaeleon I
Bibliographic record
Abstract
\n Context. It is well known that stellar companions can influence the evolution of a protoplanetary disk. Nevertheless, previous disk surveys did not – and could not – consistently exclude binaries from their samples.\n Aims. We present a study dedicated to investigating the frequency of ongoing disk accretion around single stars in a star-forming region.\n Methods. We obtained near-infrared spectroscopy of 54 low-mass stars selected from a high-angular resolution survey in the 2–3 Myr-old Chamaeleon I region to determine the presence of Brackett-γ emission, taking the residual chance of undetected multiplicity into account, which we estimate to be on the order of 30%. The result is compared with previous surveys of the same feature in binary stars of the same region to provide a robust estimate of the difference between the accretor fractions of single stars and individual components of binary systems.\n Results. We find Brγ emission among 39.5+ 14.0-9.9% of single stars, which is a significantly higher fraction than for binary stars in Chamaeleon I. In particular, close binary systems with separations <100 AU show emission in only 6.5+ 16.5-3.0% of the cases according to the same analysis. The emitter frequency of wider binaries appears consistent with the single star value. Interpreting Brγ emission as a sign of ongoing accretion and correcting for sensitivity bias, we infer an accretor fraction of single stars of Facc = 47.8+ 14.0-9.9%. This is slightly higher but consistent with previous estimates that do not clearly exclude binaries from their samples.\n Conclusions. Through our robust and consistent analysis, we confirm that the fraction of young single stars harboring accretion disks is much larger than that of close binaries at the same age. Our findings have important implications for the timescales of disk evolution and planet formation.\n
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".