Simultaneous visible spectrophotometry of interstellar object 3I/ATLAS with Seimei/TriCCS
Bibliographic record
Abstract
Abstract 3I/ATLAS, also known as C/2025 N1 (ATLAS), is the third interstellar object discovered in 2025 July. Interstellar objects are particularly interesting because characterizing their physical properties helps us improve and use our knowledge of the formation of the Solar system. Several quick response observations of 3I/ATLAS were performed during the first few days after the discovery, and various results, such as reflectance spectra, have been reported. We performed simultaneous visible spectrophotometry of 3I/ATLAS from data taken using the TriColor CMOS camera and spectrograph (TriCCS) on the Seimei 3.8 m telescope. The Seimei/TriCCS observations of 3I/ALTAS were obtained in the g, r, i, and z bands in the Pan-STARRS system on 2025 July 15 UTC. Our light curves show no significant variations during the 2.3 hr observation, which is in good agreement with the results of previous studies. Visible color indices of 3I/ATLAS, $g-r = 0.603\pm0.031$, $r-i = 0.210\pm0.031$, $i-z=0.117\pm0.046$, and $r-z = 0.327\pm0.035$ suggest that it has a red surface similar to, or slightly redder than, that of D-type asteroids. Continuous observations of 3I/ATLAS before and after its perihelion passage in 2025 October are required in order to investigate its physical properties.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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 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".