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Galaxies and the Milky Way > paper:4356v1.0
[Submitted on 2 April 2026, latest v4.0]

Orbital decay of WASP-12b re-measured from fourteen years of transit times

E. Varga, D. Imai
We fit 212 transit times of WASP-12b spanning 2008 to 2022 and find that the orbital period is decreasing at 30 ± 2 ms per year. The decay implies a stellar tidal quality factor of about 1.8 × 10^5.
Stage:T0 unverified
Highest:T4 on v4.0
Models:claude-opus-4 (Anthropic)
Writing:declared W2; no prediction; readers no votes
Analysis:declared A1; no prediction; readers no votes
Original text:100% (pct_original)
Subjects:Galaxies and the Milky Way (astro.ga)
Maintained by:E. Varga
Code:wasp12-timing at tag v4.0
Cite as:E. Varga, D. Imai. Orbital decay of WASP-12b re-measured from fourteen years of transit times. Garleak paper:4356v1.0 (T0, unverified, not peer reviewed, stage as of 2026-09-14). https://garleak.org/example/abs/4356v1.0/
License:CC BY 4.0
DOI:minted at graduation

Not peer reviewed. Admitted after screening for scope and form only. Admission is not endorsement.

Verification history

[v4.0] 9 Sep, T4 Passed, S. Haddad, computational 1.0.0. Reran the full timing pipeline on my own machines from the public light curves. Period derivative -28.9 ± 1.0 ms per year.

[v4.0] 3 Sep, T3 Passed, N. Karimi, computational 1.0.0. Refit 60 of the 318 transit times from public light curves and reran the model comparison. Period derivative within 0.3 ms per year.

[v4.0] 30 Aug, T2 Passed, J. Lindqvist, computational 1.0.0. All 8 required items pass. The Bayes factor now reproduces from the pinned code.

[v4.0] 27 Aug, T1 Passed, M. Okafor, citations 1.0.0. All 41 references exist and match their metadata.

[v3.0] 20 Jun, T2 Failed, J. Lindqvist, computational 1.0.0. The nested-sampling run does not reproduce the stated Bayes factor from the pinned code. Failed comp.T2.numbers-traceable, The pinned code gives a Bayes factor of 40 for decay over precession, not the 'decisive' preference stated..

[v3.0] 14 Jun, T1 Passed, M. Okafor, citations 1.0.0. All 40 references exist and match.

[v2.0] 20 May, T1 Passed, M. Okafor, citations 1.0.0. All 38 references exist and match.

Submission history

From: E. Varga

[v1.0] 2 April 2026, first submission, T0 , 100% original

[v1.1] 20 April 2026, minor, wording, T0 , 96% original, diff from v1.0

[v2.0] 15 May 2026, major, adds 56 transit times, T1 , 86% original, diff from v1.0

[v3.0] 10 June 2026, major, tests apsidal precession, T1 , 54% original, diff from v1.0

[v4.0] 26 August 2026, major, final data set and refit literature times, T4 , 32% original, diff from v1.0

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