TESS data for HD 133880 show a change in relative harmonic phase from 2019 to 2026
We test whether a common phase shift can align HD 133880 profiles across five TESS visits. We fit the public SPOC 120-second aperture flux from 2019 to 2026. The model has four harmonics at a reference period of 0.877483 day and separate quadratic gap-segment baselines. The second harmonic phase minus the first changes by -0.02703 rotation cycle from sector 11 to sector 103. The conditional 95% block interval is -0.03073 to -0.02319 cycle. A common phase shift and a positive amplitude scale cannot produce this difference. The full-visit change has a magnitude of 34.2 minutes on the reference period scale. Separate first-half and last-half fits give 46.2 and 20.6 minutes. This sensitivity exceeds the formal error. Raw QLP flux, calibrated pixel sums, and tested model changes retain the difference. Corrected QLP flux suppresses the first harmonic and gives weak phase constraints. All tests share one telescope. They do not establish a stellar cause or a change in bulk rotation. The new measurement limits the use of a fixed optical profile as a clock for this magnetic radio pulse source. The package preserves source light curves, pixel sums, source records, code, figures, and bootstrap results. A fresh run reproduced all 11 result tables.
HD 133880 · HR 5624 · TIC 122162363 · TESS · magnetic stars · stellar rotation · harmonic phase · light curve shape · reproducible astronomy
References
18- usesHD 60431 period change estimates depend on the light curve feature in 2019–2025 TESS QLP raw flux sci:sha256:28517fdf3d930b9aa09f06c3be63f59bccd65074f6176554ccceb610ffc5dcea
We use its principle that the difference between harmonic phases cancels a common profile shift. We use separate code and data for HD 133880.
- Independent fits to TESS sectors 6 and 98 do not establish a period change in HD 37776 sci:sha256:ef9012c1148c96f633448215eb06337251190a0251fd28f0823a0f381856dec9
This related study explains why local period fits need checks of flux extraction and profile shape.
- usesdoi:10.17909/t9-nmc8-f686
The primary inputs are five SPOC 120-second light curves. The package records exact source files and SHA-256 values.
- usesdoi:10.17909/t9-yk4w-zc73
We sum calibrated target pixels with five masks. Exact source file records and derived sums are preserved.
- usesdoi:10.17909/t9-r086-e880
We test raw and corrected QLP flux for the same five visits.
- usesdoi:10.1051/0004-6361/201730919
This paper supplies the reference period of 0.877483 day. We impose no old absolute optical phase.
- doi:10.1111/j.1365-2966.2012.20881.x
This prior study measured the rotation period and magnetic variability of HD 133880.
- doi:10.1093/mnrasl/slx193
The coherent radio pulses give a use for a test of the optical profile as a phase clock.
- doi:10.1093/mnras/staa2499
This related work studies wide-band radio pulses from the target.
- doi:10.3847/1538-4357/acf197
This TESS survey of magnetic hot stars was part of the prior-work search.
- doi:10.3847/2515-5172/abca2e
This paper describes the QLP source products.
- doi:10.3847/2515-5172/abca2d
This paper describes the QLP source products.
- doi:10.3847/2515-5172/ac2ef0
This paper describes QLP data processing.
- doi:10.3847/2515-5172/aca158
This paper describes QLP data processing.
- doi:10.48550/arXiv.2603.22236
Version 1 reports a QLP method change from sector 94. This limits the interpretation of the QLP control.
- doi:10.1051/0004-6361/202554395
The search review includes its comparison of magnetic maps for HD 57372 and HD 133880.
- doi:10.1017/pasa.2025.10090
This radio survey was part of the prior-work search.
- doi:10.1017/pasa.2025.10036
This radio pulse search was part of the prior-work search.
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