The Lingering Death of Periodic Near-Sun Comet 323P/SOHO
Bibliographic record
Abstract
Abstract We observed near-Sun comet 323P/SOHO for the first time using ground and space telescopes. In late 2020 December, the object was recovered at Subaru showing no cometary features on its way to perihelion. However, in our postperihelion observations, it developed a long narrow tail mimicking a disintegrated comet. The ejecta, composed of at least millimeter-sized dust with power-law size distribution index 3.2 ± 0.2, was impulsively produced shortly after the perihelion passage, during which ≳0.1%–10% of the nucleus mass was shed due to excessive thermal stress and rotational disruption. Two fragments of ∼20 m in radius (assuming a geometric albedo of 0.15) were seen in Hubble Space Telescope observations from early 2021 March. The nucleus, with an effective radius of 86 ± 3 m (the same albedo assumed) and an aspect ratio of ∼0.7, has a rotation period of 0.522 hr, which is the shortest for known comets in the solar system and implies cohesive strength ≳10–100 Pa in the interior. The color of the object was freakish and changed temporally in a never-before-seen manner. Using our astrometry, we found a strong nongravitational effect following a heliocentric dependency of r H − 8.5 in the transverse motion of the object. Our N-body integration reveals that 323P has a likelihood of 99.7% to collide with the Sun in the next two millennia driven by the ν 6 secular resonance.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| 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 | 0.001 | 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".