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

A coplanar two-planet fit to 35 early TOI-2202 b times has a 37-minute RMS error on 15 later times

We tested a reduced Newtonian model of the known TOI-2202 planet pair. We fit 35 unique transit times from 2018–2023 and tested 15 later times from 2024–2025. The selected coplanar, edge-on fit has a fixed planet b mass of 0.95 Jupiter mass. Its root mean square timing error is 7.45 minutes early and 37.06 minutes later. The largest later error is 65.63 minutes. A sine fit on the same early inputs gives a later error of 46.19 minutes. Four early-data sensitivity fits give later errors from 36.26 to 38.44 minutes. The early Newtonian chi-square is 855.53 for 26 degrees of freedom. Thus, this selected fit does not give a precise transit schedule under the stated time errors. The search is bounded and incomplete. This retrospective test does not exclude the published full orbit model or establish a new planet. We also test orbit input conventions in REBOUND 5.2.2 and TTVFast 0.3.0. For one nominal orbit, direct element copying gives a maximum timing difference of 5.11 hours. A common Cartesian state reduces this to 0.431 seconds at a 0.15-day step. The package preserves source tables, provenance, code, orbit states, predictions, numerical checks, figures, and reproduction commands.

TOI-2202 · transit timing variations · TESS · Newtonian model · prediction test · orbit conventions · reproducible astronomy

Admitted 1 citing publication

References

10
  1. usesA sine model fit to TOI-2202 b in 2020–2023 has a 2024–2025 RMS timing error of 35 minutes sci:sha256:eae8c09f41121578f2580d7101c5698713d40dfa4b51d39100d110f92eb0b41a

    We use 32 archived TESS times, source timing tables, light-curve checks, and the MIT empirical comparison code. We test a reduced Newtonian model with a different common early input set.

  2. usesEighteen TESS transits extend the TOI-2202 b timing record to September 2025 sci:sha256:f177d4c25dc5637319e38711095b8e56a3f8edc12b83fc7bdc2a028829555f00

    We use its accepted timing table to check measurements from the same TESS photons. We do not count this reduction as independent astronomical evidence.

  3. usesdoi:10.3847/1538-3881/ac1bbe

    We use 13 discovery transit times, the star mass, and starting orbit and geometry values. The reduced timing-only model does not reproduce the full published analysis.

  4. usesdoi:10.3847/1538-3881/ad09de

    We use five independent ground transit times. We add its unique epoch minus 39 TESS time in a sensitivity fit.

  5. doi:10.1051/0004-6361/202557512

    This TESS timing catalogue gives prior context for an updated orbit analysis. Its source table is retained as context, outside the main fit.

  6. usesdoi:10.17909/t9-nmc8-f686

    The reused transit times come from public TESS light curves at MAST. The parent SCI record preserves the original files and reduction provenance.

  7. usesdoi:10.1051/0004-6361/201118085

    REBOUND builds and integrates the Newtonian three-body state.

  8. usesdoi:10.1093/mnras/stu2164

    IAS15 supplies high-accuracy final transit predictions and the integration reference.

  9. usesdoi:10.1093/mnras/stv1257

    WHFast with IAS15 transit refinement supplies a numerical convergence check.

  10. usesdoi:10.1088/0004-637X/787/2/132

    TTVFast supplies the fast fit calculation. A controlled test compares element input with a common Cartesian input state.

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