Hot nights on extrasolar planets: mid-infrared phase variations of hot Jupiters
Bibliographic record
Abstract
We present results from Spitzer Space Telescope observations of the mid-infrared phase variations of three short-period extrasolar planetary systems: HD 209458, HD 179949 and 51 Peg. We gathered Infrared Array Camera (IRAC) images in multiple wavebands (3.6 or 4.5 and 8 μm) at eight phases of each planet's orbit. We find the uncertainty in relative photometry from one epoch to the next to be significantly larger than the photon counting error at 3.6 and 4.5 μm. We are able to place 2σ upper limits of only ∼2 per cent on the phase variations at these wavelengths. At 8 μm, the epoch-to-epoch systematic uncertainty is comparable to the photon counting noise and we detect a phase function for HD 179949 which is in phase with the planet's orbit and with a relative peak-to-trough amplitude of 0.001 41 (33). Assuming that HD 179949b has a radius RJ < Rp < 1.2RJ, it must recirculate less than 21 per cent of incident stellar energy to its night side at the 1σ level (less than 26 per cent at the 2σ level, where 50 per cent signifies full recirculation). If the planet has a small Bond albedo, it must have a mass less than 2.4MJ(1σ). We do not detect phase variations for the other two systems but we do place the following 2σ upper limits: 0.0007 for 51 Peg and 0.0015 for HD 209458. Due to its edge-on configuration, the upper limit for HD 209458 translates, with appropriate assumptions about Bond albedo, into a lower limit on the recirculation occuring in the planet's atmosphere. HD 209458b must recirculate at least 32 per cent of incident stellar energy to its night side, at the 1σ level (at least 16 per cent at the 2σ level), which is consistent with other constraints on recirculation from the depth of secondary eclipse depth at 8 μm and the low optical albedo. These data indicate that different hot Jupiter planets may experience different recirculation efficiencies.
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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 | 0.000 |
| 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) | 0.000 | 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".