The fall and recovery of the Tagish Lake meteorite
Why this work is in the frame
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Bibliographic record
Abstract
Abstract— The Tagish Lake C2 (ungrouped) carbonaceous chondrite fall of January 18, 2000, delivered ˜10 kg of one of the most primitive and physically weak meteorites yet studied. In this paper, we report the detailed circumstances of the fall and the recovery of all documented Tagish Lake fragments from a strewnfield at least 16 km long and 3 to 4 km wide. Nearly 1 kg of “pristine” meteorites were collected one week after the fall before new snow covered the strewnfield; the majority of the recovered mass was collected during the spring melt. Ground eyewitnesses and a variety of instrument‐recorded observations of the Tagish Lake fireball provide a refined estimate of the fireball trajectory. From its calculated orbit and its similarity to the remotely sensed properties of the D‐ and P‐class asteroids, the Tagish Lake carbonaceous chondrite apparently represents these outer belt asteroids. The cosmogenic nuclide results and modeled production indicate a prefall radius of 2.1–2.4 m (corresponding to 60–90 tons) consistent with the observed fireball energy release. The bulk oxygen‐isotope compositions plot just below the terrestrial fractionation line (TFL), following a trend similar to the CM meteorite mixing line. The bulk density of the Tagish Lake material (1.64 ± 0.02 g/cm 3 ) is the same, within uncertainty, as the total bulk densities of several C‐class and especially D‐ and P‐class asteroids. The high microporosity of Tagish Lake samples (˜40%) provides an obvious candidate material for the composition of low bulk density primitive asteroids.
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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 | 0.001 | 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 it