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

Periods from the reference time source reduced the median TESS offset from 9.0 to 0.62 minutes for 51 tested hot Jupiters

A transit prediction needs a reference time and an orbital period. We tested whether using the period from the source of the reference time improves agreement with saved TESS transit times. We matched the NASA Exoplanet Archive composite table to its published source records in a fixed snapshot from 2026-10-21 UTC. Of 153 planets in an earlier SCI timing report, 145 have complete source matches. In 51 cases, the original period and reference time have different sources. We kept the reference time and its error unchanged. We selected the replacement period by its source, without using agreement with TESS. The median absolute time residual decreased from 8.98 to 0.625 minutes. Forty-six cases improved, four worsened, and one was unchanged. Cases above 10 minutes decreased from 24 to two. In 45 cases with an explicit BJD-TDB source label, the median decreased from 8.98 to 0.566 minutes. All 94 same-source controls were unchanged. Separate Decimal arithmetic verified the calculation. Repeating the earlier fit on seven public light curves recovered the saved individual times within one second. Forty-seven original periods come from one older table. The test therefore cannot separate source consistency from newer or more precise periods. The contribution is a measured source-based substitution test, a complete selection ledger, and software for its inspection. We supply source snapshots, data provenance, public light curves, code, figures, and reproduction commands. This study does not test the archive prediction service or claim a new planet or orbital period change.

transit timing · ephemeris · TESS · NASA Exoplanet Archive · hot Jupiters · data provenance · reproducible astronomy

Admitted 1 citing publication

References

11
  1. usesTESS 2-minute transit times of 153 bright hot Jupiters missed the NASA Exoplanet Archive default ephemeris predictions by more than 3 sigma for 33 planets (sectors 21-107) sci:sha256:1895bf428f65ddb5d621f1e1b67e6fe70b4074599f4ced66ffdc1cf0a99b69fe

    We reuse its individual transit times, sample selection, source code, and input files. We repeat its fit for seven selected public light curves. We add a test that uses the period from the source of each reference time.

  2. usesdoi:10.26133/NEA12

    The saved Planetary Systems table supplies the published source parameter sets.

  3. usesdoi:10.26133/NEA13

    The saved Planetary Systems Composite Parameters table supplies the tested original periods and reference times.

  4. usesdoi:10.1117/1.JATIS.1.1.014003

    The TESS mission supplied the public light curves used by the earlier measurement and the seven replays.

  5. usesdoi:10.3847/1538-4365/ac3a10

    ExoClock II supplies five matched periods in the main test. Its source table confirms the HAT-P-3 b values.

  6. usesdoi:10.3847/1538-4365/ac9da4

    ExoClock III supplies 30 matched periods in the main test.

  7. usesdoi:10.3847/1538-4365/ac545b

    Ivshina and Winn supply four matched periods and provide prior work on large TESS timing samples.

  8. usesdoi:10.3847/1538-3881/aa5df3

    This table supplies 47 of the 51 original composite periods. This concentration limits interpretation of the source substitution.

  9. usesdoi:10.1093/mnras/staa814

    This paper supplies the WASP-100 b source ephemeris. Its reference-time table motivates a time-origin check.

  10. doi:10.3847/1538-3881/ab845d

    This paper studies the loss of precision in transit predictions as their epochs become old.

  11. doi:10.3847/1538-4365/ae3238

    ExoClock IV is a newer catalog of 620 updated ephemerides. The present test does not select the best current catalog.

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