X-ray emission of brown dwarfs: towards constraining the dependence on age, luminosity, and temperature
Bibliographic record
Abstract
Three brown dwarfs in different evolutionary stages have been observed with the Chandra X-ray Observatory. Combining the new observations with previous studies presented in the literature yields a brown dwarf sample that reaches well down into the cooling phase of brown dwarfs, allowing to investigate the possible influence of effective temperature on X-ray activity. Combining our results with published data allows us to consider a subsample of high-mass brown dwarfs (with 0.05-0.07 Msun), and another one characterized by similar effective temperature (with 2400-2800 K). Our findings support the idea that effective temperature plays a critical role for the X-ray activity in brown dwarfs. This underlines an earlier suggestion based on observations of chromospheric Ha emission in ultracool dwarfs that the low ionization fraction in the cool brown dwarf atmospheres may suppress magnetic activity.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 | 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 teacher head, 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".