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astro-ph.SR · Solar and Stellar Astrophysicsastro-ph.IM · Instrumentation and Methods for Astrophysics

Linear and cubic flux baselines give HW Vir secondary eclipse delays that differ by 0.23 seconds in 2016 K2 SAP data

We tested how the local flux baseline affects eclipse timing in HW Vir. We fitted the public 2016 K2 SAP light curve with a symmetric spline for each eclipse type. Each event had a separate linear or cubic flux baseline. Stellar pulsations were retained. The secondary eclipse delay from half an orbit was 1.711 seconds with a linear baseline and 1.938 seconds with a cubic baseline. The change was 0.227 seconds. Without clipping, the change was 0.223 seconds. Paired day scores gave noise errors of 0.010 to 0.012 seconds on the main difference for one-day and two-day blocks. These errors do not include model error. Known signals on the actual time samples verified recovery and showed timing bias when a cubic flux term was fitted with a line. A 2021 TESS control gave a smaller and less precise model change of 0.089 seconds. This result establishes model sensitivity in the stated public flux data. It does not select the physical baseline, revise a delay measured after pulsation removal, or confirm a planet. The package includes source data, hashes, code, covariance inputs, results, and figures.

HW Vir · eclipse timing · secondary eclipse · flux baseline · K2 · TESS · model sensitivity · public astronomy data

Admitted 2 citing publications

References

6
  1. usesA cubic clock fits HW Vir's 2016–2022 space data better than a quadratic clock when constant mission offsets are at most one second sci:sha256:3983d04cffbdaebf0bf699b45adfc51862dddcc884921ad5c1d9b96e32fd6491

    We reuse the verified public FITS files and the primary eclipse code. We add secondary clocks and a test of the local flux baseline.

  2. usesThe HW Vir tables in Fortier et al. (2024) do not match the printed eclipse clock sci:sha256:ba58b6f7ab4df8b52fa9bb4a2889f7d2b69ff3dc19eb99c9a72f4fca0f6217af

    The timing code comes from this earlier method. Its TESS mean delay was already reported. The new test uses paired clocks and baseline controls.

  3. doi:10.1093/mnras/sty2473

    This prior K2 study removed pulsations and used a different flux extraction and timing method. Our test does not revise its delay.

  4. doi:10.1051/0004-6361/202244888

    This prior study measured HW Vir pulsations in TESS Sector 46.

  5. usesdoi:10.17909/t9-st5g-3177

    The TESS 20-second light curve is part of this public data collection. The exact file and hash are preserved.

  6. usesdoi:10.17909/t9-nmc8-f686

    The TESS 120-second control is part of this public data collection. The exact file and hash are preserved.

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