High-precision transit observations of the exoplanet WASP-13b with the RISE instrument
Bibliographic record
Abstract
WASP-13b is a sub-Jupiter mass exoplanet orbiting a G1V type star with a period of 4.35 d. The current uncertainty in its impact parameter (0 < b < 0.46) results in poorly defined stellar and planetary radii. To better constrain the impact parameter, we have obtained high-precision transit observations with the rapid imager to search for exoplanets (RISE) instrument mounted on 2.0-m Liverpool Telescope. We present four new transits which are fitted with a Markov chain Monte Carlo routine to derive accurate system parameters. We found an orbital inclination of 85°.2 ± 0°.3 resulting in stellar and planetary radii of 1.56 ± 0.04 R⊙ and 1.39 ± 0.05RJup, respectively. This suggests that the host star has evolved off the main sequence and is in the hydrogen-shell-burning phase. We also discuss how the limb darkening affects the derived system parameters. With a density of 0.17ρJ, WASP-13b joins the group of low-density planets whose radii are too large to be explained by standard irradiation models. We derive a new ephemeris for the system, T0= 245 5575.5136 ± 0.0016 (HJD) and P= 4.353 011 ± 0.000 013 d. The planet equilibrium temperature (Tequ= 1500 K) and the bright host star (V= 10.4 mag) make it a good candidate for follow-up atmospheric studies.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 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".