EARLY ASTEROSEISMIC RESULTS FROM <i>KEPLER</i> : STRUCTURAL AND CORE PARAMETERS OF THE HOT B SUBDWARF KPD 1943+4058 AS INFERRED FROM <i>g</i> -MODE OSCILLATIONS
Bibliographic record
Abstract
We present a seismic analysis of the pulsating hot B subdwarf KPD 1943+4058 (KIC 005807616) on the basis of the long-period, gravity-mode pulsations recently uncovered by Kepler . This is the first time that g -mode seismology can be exploited quantitatively for stars on the extreme horizontal branch, all previous successful seismic analyses having been confined so far to short-period, p -mode pulsators. We demonstrate that current models of hot B subdwarfs can quite well explain the observed g -mode periods, while being consistent with independent constraints provided by spectroscopy. We identify the 18 pulsations retained in our analysis as low-degree (ℓ = 1 and 2), intermediate-order ( k = −9 through −58) g -modes. The periods (frequencies) are recovered, on average, at the 0.22% level, which is comparable to the best results obtained for p -mode pulsators. We infer the following structural and core parameters for KPD 1943+4058 (formal fitting uncertainties only): T eff = 28,050 ± 470 K, log g = 5.52 ± 0.03, M * = 0.496 ± 0.002 M ☉ , log ( M env / M * ) = −2.55 ± 0.07, log (1 − M core / M * ) = −0.37 ± 0.01, and X core (C+O) = 0.261 ± 0.008. We additionally derive the age of the star since the zero-age extended horizontal branch 18.4 ± 1.0 Myr, the radius R = 0.203 ± 0.007 R ☉ , the luminosity L = 22.9 ± 3.13 L ☉ , the absolute magnitude M V = 4.21 ± 0.11, the reddening index E ( B − V ) = 0.094 ± 0.017, and the distance d = 1180 ± 95 pc.
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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 | 0.001 | 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 | 0.000 |
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".