New asteroid clusters and evidence of collisional fragmentation in the L<sub>5</sub> Trojan cloud of Mars
Bibliographic record
Abstract
Context. Trojan asteroids of Mars date from an early phase of Solar System evolution. The Mars Trojan (MT) distribution has been previously shown to be highly asymmetric and inhomogeneous. Remarkably, a single asteroid family associated with (5261) Eureka (H ∼ 16) at L5 contains all stable Trojans fainter than H = 18. A possible culprit is the action of thermal radiation forces on the orbits and rotation states of these small asteroids. Aims. Using a larger MT sample than previously available, we took a fresh look at this population to re-evaluate these earlier conclusions. We also searched for additional features diagnostic of MT evolutionary history and of the Eureka family in particular. Methods. We performed harmonic analysis on numerical time series of the osculating elements to compile a new proper element catalogue comprising 16 L5 and 1 L4 MT asteroids. We then combined sample variance analysis with statistical hypothesis testing to identify clusters in the distribution of orbits and assess their significance. Results. We identify two small clusterings significant at 95% confidence of three H=20−21 asteroids each and investigate their likely origin. One of the clusters is probably the result of rotational breakup of a Eureka family asteroid ∼108 yr ago. The significantly higher tadpole libration width of asteroids in the other cluster is more consistent with an origin as impact ejecta from Eureka itself on a timescale comparable to the ∼1 gigayear age of its family. We further confirm the previously reported correlations in Eureka family orbital distribution attributed to the long-term action of radiation-driven forces and torques on the asteroids.
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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 | 0.000 | 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".