The Age of the Inner Halo Globular Cluster NGC 6652
Bibliographic record
Abstract
Hubble Space Telescope ( V , I ) photometry has been obtained for the inner halo globular cluster NGC 6652. The photometry reaches ∼4 mag below the turnoff and includes a well-populated horizontal branch. This cluster is located close to the Galactic center, at R GC ≃ 2.0 kpc, with a reddening of E ( V - I ) = 0.15 ± 0.02, and has a metallicity of [Fe/H] ≃ -0.85. Based upon Δ V , NGC 6652 is 11.7 ± 1.6 Gyr old. Using Δ V , precise differential ages for 47 Tuc (a thick disk globular cluster), M107, and NGC 1851 (both halo clusters) were obtained. NGC 6652 appears to be the same age as 47 Tuc and NGC 1851 (within ±1.2 Gyr), while there is a slight suggestion that M107 is older than NGC 6652 by 2.3 ± 1.5 Gyr. As this is a less than 2 σ result, this issue needs to be investigated further before a definitive statement regarding the relative age of M107 and NGC 6652 may be made.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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 | 0.001 |
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".