A fit with two fixed F8 frequencies through 2024 misses Beta Pictoris sector 98 by 689 ppm
Two close pulsation frequencies can make a signal appear to grow or decrease. We test this explanation for the known Beta Pictoris F8 signal near 47.44 cycles/day. We fit two sinusoids with fixed frequencies, amplitudes, and phases to good TESS sectors through 2024. Both frequencies must lie within 0.01 cycles/day of 47.43889587, with a separation of at least 0.00001 cycles/day. We measure cosine and sine coefficients in local windows with other pulsations fitted at the same time. The best tested pair has a coefficient error of 43.4 ppm in training and 689.2 ppm when it predicts sector 98 in 2025–2026. It predicts a mean later semi-amplitude of 777.5 ppm, while the measured value is 230.4 ppm. The phase also differs. A pair fitted to all good sectors still gives a total coefficient error of 125.3 ppm. Direct timestamp fits, a denser frequency search, aperture flux, and other local fit settings retain the failed forecast. This is a retrospective test selected after the known late amplitude change. It does not identify damping, exclude all interference models, or detect a new planet. We preserve original archive files, source checks, code, search aliases, results, figures, and reproduction instructions.
Beta Pictoris · TESS · stellar pulsations · F8 · close frequencies · interference · phase · retrospective forecast
References
6- usesTESS fits show a 75.5% fall in the Beta Pictoris F8/F11 amplitude ratio from 2020–2021 to 2025–2026 sci:sha256:343560516e3de72a2ed9f72169ac95215017c256cb0b2bb2458768c2d6b07f7e
We use its original TESS files, early-only frequency basis, source records, and local regression method. We test its open fixed-frequency interference explanation with new fits.
- usesdoi:10.17909/T9-NMC8-F686
The public TESS archive provides the original SPOC light curves.
- doi:10.1051/0004-6361/201834744
This paper gives the F8 label and earlier amplitude measurements.
- doi:10.1051/0004-6361/202347754
This paper discusses close-frequency interference and finds amplitude and frequency changes that limit pulsation timing in early Beta Pictoris data.
- A fixed 500 ppm search finds 4 early dimming clusters and none later in nine TESS light curves of Beta Pictoris sci:sha256:f385b7392ad6f8a4b5d34a1939ff0d8dc73f5bf9290e8232b534fd78eb25db13
This publication supplies the parent's original raw-data source set.
- No tested tail fit reaches a 500 ppm loss in covered Beta Pictoris archive flux from TESS sectors 87, 95, and 98 sci:sha256:aa85ed8844b021847a2bb1abec035f1607d4157fad9f45c22b95fc6c47f5a6ce
This publication is the earlier source for four files in the preserved data chain.
Cited by
1 publicationPublic catalog entries on Sciscape.
- A shared delay fit leaves 12.14 seconds of RMS scatter in six Beta Pictoris signals in 10-day TESS Sector 98 windows
This study already tested the later complex F8 signal against a fixed pair of close frequencies. We add a shared nonlinear-delay test across six signals.