Local fits give apparent decreases at eclipse and phase 0.75 in six WASP-121 b TESS sectors
Can public TESS data show a change in the optical eclipse depth of WASP-121 b? We fit 103 eclipses in six unchanged SPOC 120-second light curves from Sectors 7, 33, 34, 61, 87, and 88. The circular orbit, geometry, and transit clock are fixed. Local quadratic fits give a change of -165 parts per million (ppm) from 2019 to 2024–2025. A circular block bootstrap gives a nominal 95% interval of -263 to -66 ppm. The same template at phase 0.75, where no eclipse occurs in this model, gives -167 ppm with an interval of -329 to -8 ppm. These samples have different accepted orbits. On 100 common orbits, the change in eclipse depth minus control depth is -37 ppm, with an interval of -232 to +158 ppm. The matched control interval includes zero. Thus the local fits do not separate the two changes well. This does not prove equal signals, a constant planet, or an instrument cause. Tested fit choices change the estimated eclipse decrease from about 105 to 195 ppm. The uncertainty model omits errors shared by a whole sector. We do not identify a change in the atmosphere. The package supplies source FITS data, provenance, all estimates and selection records, bootstrap results, injections, figures, new code, and instructions. An independent full run reproduces the saved numeric results.
WASP-121 b · TESS · secondary eclipse · optical phase curve · control phases · correlated noise · reproducible astronomy
References
7- usesA constant period fits 103 WASP-121 b TESS transit times with a shared transit shape and independent errors sci:sha256:94fe4fe6d43a900b8047b3022de309095a752e581f3e9b6d199acbcf6596ebd8
We use its six unchanged MAST source light curves and constant-period transit clock. We make new eclipse and control measurements with new code.
- usesdoi:10.17909/t9-nmc8-f686
MAST source dataset for the six public TESS SPOC 120-second light curves. Exact filenames, URLs, processing versions, and hashes are preserved.
- usesdoi:10.1051/0004-6361/201936647
We use its fixed system geometry and test its two Sector 7 ramp exclusions. Its early phase-curve result gives prior context.
- doi:10.3847/1538-3881/abd8d2
Its Sector 7 phase-curve study and reported corrected-flux residuals motivate the SAP flux control.
- doi:10.1093/mnras/stae2419
Its phase-curve study combines the first three sectors. It gives prior context; our local estimates do not reproduce its full model.
- doi:10.3847/1538-4365/ad1191
Its Hubble spectral variability result motivates a careful test of optical changes. The dates and wavelengths differ.
- usesdoi:10.1086/683602
We use batman for an independent check of the circle-overlap eclipse geometry and exposure integration.
Cited by
3 publicationsPublic catalog entries on Sciscape.
- Uniform TESS 120-s photometry (Sectors 1–107) detects eclipses of 35 of 420 hot Jupiters at z ≥ 3 (2.2 false expected), 9 with no published TESS depth; blackbody emission explains the stacked depths
A control phase at 0.75 gave an apparent depth change as large as the eclipse change for WASP-121 b. This is an example of the false-phase signals that our null calibration measures for all planets.
- usesA full orbit model leaves the eclipse depth change unresolved in six WASP-121 b TESS sectors
We reuse its six source light curves, fixed orbit, quality mask, eclipse template, loader, local estimator, and geometry checks. We test its requested full phase curve follow-up. The unchanged MIT code and attribution are preserved.
- A periodic flux model reduces eclipse scatter in four WASP-178 TESS sectors under a circular orbit
Its eclipse and control-phase results motivate control fits. Our target data and code are independent.