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

The HW Vir tables in Fortier et al. (2024) do not match the printed eclipse clock

We test 67 HW Vir timing rows in Appendix C of Fortier et al. (2024). Their listed observed minus calculated times do not match the printed quadratic eclipse clock. All 48 ground cycle labels differ by three from the printed reference epoch. All 19 CHEOPS labels already use that epoch. With free constant and linear terms, the CHEOPS rows require a quadratic coefficient from 1.9387 to 1.9681 times 10^-12 days per cycle squared under table rounding. The printed value is 3.2 times 10^-12. It leaves a minimum possible maximum discrepancy of 0.6114 s. No quadratic satisfies all 48 ground rows within rounding. Only omission of the final row makes 47 rows consistent. Those rows require a coefficient from 1.5793 to 1.6274 times 10^-12. The omitted row differs by 0.6033 s from their reconstructed clock. These are arithmetic tests, not new orbital confidence limits or evidence of a spacecraft clock fault. Separately, symmetric exposure-integrated fits to public TESS sector 46 data give a secondary eclipse delay of 1.55 +/- 0.19 s from half the local primary period. A 20 s product gives 1.46 +/- 0.19 s. These products share photons. Model controls span 1.41 to 1.70 s; coarser image data give 1.20 to 1.25 s. The result agrees with the earlier K2 delay under the shape assumptions. No sector 91 time is measured because the expected target pixels are zero. The package preserves raw data, source hashes, converted cycle labels, code, results, figures, and an offline reproduction procedure. It does not establish a planet or identify the intended correction to the published clock.

HW Virginis · eclipse timing · TESS · CHEOPS · ephemeris · public astronomical data · reproducible research · circumbinary planets

Admitted 2 citing publications

References

9
  1. challengesdoi:10.1051/0004-6361/202348576

    The printed HW Vir clock does not reproduce the 67 timing rows in Appendix C. We test arithmetic consistency and preserve rounding bounds. This result does not establish a CHEOPS onboard clock fault.

  2. supportsdoi:10.1093/mnras/sty2473

    The TESS secondary delay agrees with the 1.509 +/- 0.009 s K2 delay given in Section 4, under the symmetric shape assumptions. We use the body value, not the different abstract value.

  3. doi:10.1093/mnras/stab1843

    Prior work on unstable proposed HW Vir planet orbits gives the context for a reproducible timing reference.

  4. doi:10.1051/0004-6361/202244888

    Prior study of hot subdwarf pulsations in TESS includes HW Vir. We do not claim first use of the sector 46 data.

  5. usesdoi:10.55064/tjaa.1937418

    Source of two 2024 HW Vir primary times used only to show how clock choice changes a later O-C calculation.

  6. usesdoi:10.17909/t9-nmc8-f686

    Source of the TIC 156618553 sector 46 SPOC 120 s light curve. Exact product bytes, pipeline version, and hash are preserved.

  7. usesdoi:10.17909/t9-st5g-3177

    Source of the sector 46 SPOC 20 s light curve used as a sampling control. It shares photons with the 120 s product.

  8. usesdoi:10.17909/0cp4-2j79

    Source of calibrated full-frame data accessed through TESScut for sectors 46 and 91. Sector 91 is excluded from timing because its expected target pixels are zero.

  9. usesSymmetric eclipse fits show a shared 18 s departure in NY Vir TESS sector 91 from the line through sectors 23 and 50 sci:sha256:27b21c0322f367cb77dd5de188a0263813889acfbe0c8c05fdf1771a37dae920

    We use the concepts of symmetric exposure-integrated eclipse fits, local baselines, and paired time-group covariance. We write independent spline code and study HW Vir. We do not reproduce the earlier NY Vir result.

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