Empirically Constrained Color-Temperature Relations. II.<i>uvby</i>
Bibliographic record
Abstract
A new grid of theoretical color indices for the Strömgren uvby photometric system has been derived from MARCS model atmospheres and SSG synthetic spectra for cool dwarf and giant stars having -3.0 ≤ [Fe/H] ≤ +0.5 and 3000 ≤ T eff ≤ 8000 K. At warmer temperatures (i.e., 8000 < T eff ≤ 40,000 K), this grid has been supplemented with the synthetic uvby colors from recent Kurucz atmospheric models without overshooting (Castelli, Gratton, & Kurucz, published in 1997). Our transformations appear to reproduce the observed colors of extremely metal-poor turnoff and giant stars: the various uvby color-magnitude diagrams (CMDs) for the [Fe/H] ∼ -2.2 globular cluster M92 can be matched exceedingly well down to M V ≈ 6 by the same isochrone that provides a very good fit to published BV data (see Paper I), on the assumption of the same distance and reddening. Due to a number of assumptions made in the synthetic color calculations, however, our color- T eff relations for cool stars fail to provide a suitable match to the uvby photometry of both cluster and field stars having [Fe/H] > -2.0. To overcome this problem, the theoretical indices at intermediate and high metallicities have been corrected using a set of color calibrations based on field stars having well-determined distances from Hipparcos , accurate T eff estimates from the infrared flux method, and spectroscopic [Fe/H] values. In contrast with Paper I, star clusters played only a minor role in this analysis in that they provided a supplementary constraint on the color corrections for cool dwarf stars with T eff ≤ 5500 K. They were mainly used to test the color- T eff relations and, encouragingly, isochrones that employ the transformations derived in this study are able to reproduce the observed CMDs (involving u - v , v - b , and b - y colors) for a number of open and globular clusters (including M67, the Hyades, and 47 Tuc) rather well. Moreover, our interpretations of such data are very similar, if not identical, with those given in Paper I from a consideration of BV ( RI ) C observations for the same clusters—which provides a compelling argument in support of the color- T eff relations that are reported in both studies. In the present investigation, we have also analyzed the observed Strömgren photometry for the classic Population II subdwarfs, compared our "final" ( b - y )– T eff relationship with those derived empirically in a number of recent studies and examined in some detail the dependence of the m 1 index on [Fe/H].
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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 | 0.001 | 0.006 |
| 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 | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".