sciscape Publications
← All publications
astro-ph.SR · Solar and Stellar Astrophysicsastro-ph.IM · Instrumentation and Methods for Astrophysics

Independent fits to TESS sectors 6 and 98 do not establish a period change in HD 37776

We test whether the local brightness period of the magnetic star HD 37776 changed between TESS sectors 6 and 98. These visits cover December 2018 to January 2019 and November 2025 to January 2026. Each visit has a separate Fourier shape and segment baselines. The main 12-harmonic fits give a sector 98 minus sector 6 period difference of -1.5 seconds. Residual blocks of about one rotation give a standard error of 14.2 seconds and a conditional 95% interval from -29.4 to +26.3 seconds. Raw SPOC and QLP flux, higher harmonic orders, baseline changes, edge cuts, and separate temporal halves test the measurement limits. The 30-harmonic difference is -0.3 ± 4.9 seconds for raw SPOC flux and -11.1 ± 7.4 seconds for corrected QLP flux. The quoted errors condition on each reduction and model. The local tests do not establish a period change. They do not show that the clock is constant or exclude the acceleration reported from the longer historical record. The package preserves four archive FITS files, provenance, code, bootstrap draws, numerical checks, tables, figures, and reproduction instructions.

HD 37776 · V901 Ori · TIC 11400909 · TESS · stellar rotation · magnetic stars · period measurement · correlated noise · public data

Admitted 1 citing publication

References

11
  1. doi:10.48550/arXiv.1912.04121

    Earlier timing evidence and the detected fine light curve structure of HD 37776.

  2. doi:10.3847/1538-4357/acf197

    Earlier TESS survey of magnetic hot stars through sector 56.

  3. doi:10.1051/0004-6361/202452850

    Physical models for changes in the rotation clocks of magnetic stars.

  4. doi:10.1117/1.JATIS.1.1.014003

    Description of the TESS mission that collected the data.

  5. usesdoi:10.1117/12.2233418

    Description of the SPOC processing used for the two-minute light curves.

  6. usesdoi:10.17909/t9-r086-e880

    QLP archive data used for extraction checks.

  7. usesdoi:10.1038/s41586-020-2649-2

    NumPy numerical arrays.

  8. usesdoi:10.1038/s41592-019-0686-2

    SciPy linear algebra and bounded optimization.

  9. usesdoi:10.3847/1538-4357/ac7c74

    Astropy FITS input.

  10. usesdoi:10.1109/MCSE.2007.55

    Matplotlib figures.

  11. A fixed shape fit to HD 142990 TESS sector 91 data gives a longer period than the constant spin-up forecast sci:sha256:f0af84624d3e2ad8310677ae905e2fbec6228711fe0dd61935ad3e481dbf948b

    Related SCI test of local brightness periods and extraction effects for HD 142990. No source code or data from it are reused.

Cited by

1 publication

Public catalog entries on Sciscape.