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

A 1417-day term reverses the prediction gain at a fixed 71.45-day period in the GJ 9527 HARPS velocity difference

We tested 57 fixed HARPS candidate periods in the velocity difference between DRS and SERVAL. Both reductions use the same spectra. Each linear fit used paired rows, common weights, and exposure-averaged bases. We predicted complete groups of omitted nights. At the reference setting, 10 of 33 scored candidates had lower difference prediction loss with a circular target term. Only 28 candidates had scores at all 12 main settings. GJ9527_1 at 71.446577 days and GJ3187_2 at 374.072010 days gave gains of at least 44.61% and 38.83% across those settings. The GJ9527 reference gain was 55.95%. One early group supplied 74.70% of baseline loss. Without its saved test losses, the pooled gain was -72.02%. We then added controls from prior case studies. We added sine and cosine terms at the reported 1417-day cycle to both GJ9527 models. The target gain changed to -151.62% on the same 29 test nights. A 365.25636-day pair reduced the GJ3187 gain from 39.52% to 8.24% on the same 56 test nights. These case controls were added after the complete screen. The package includes 251 known-label comparison records, exact source rows, signed input records, all folds, code, figures, and offline checks. Periods, selection, and quality rules use the full historical record. The scores are conditional prediction losses, not blind detection probabilities. The result shows sensitivity to the stated nuisance terms and test groups. It does not identify a physical cause or confirm or reject a planet.

HARPS · radial velocity · SERVAL · DRS · GJ 9527 · GJ 3187 · prediction · stellar activity · reproducible research

Admitted 2 citing publications

References

11
  1. usesdoi:10.1051/0004-6361/202348263

    HARPS-RVBank v2 provides the paired velocities and exposure metadata.

  2. usesdoi:10.26093/cds/vizier.36830125

    We use the Table 4 release corrected on 20 April 2026 and preserve exact selected rows.

  3. doi:10.1051/0004-6361/201936686

    This paper describes the first HARPS-RVBank release and reduction corrections.

  4. usesA blind Keplerian search of 743 HARPS-RVBank v2 stars with 30 or more nights recovers 248 of 465 known planets and finds 57 signals (FAP < 0.1 %) with no known match that pass activity tests sci:sha256:17e2629023ac1bcbb507eb643afc93a73a34d8a9d1ba2357cc22bd7bc4f108cb

    This search defined the candidate periods and source orbit shapes. We obtain the exact reduced records through f620c79f-04b3-40ff-bf4f-b58e8f31817a.

  5. uses29 of 57 HARPS candidates reduce season error at all 12 settings with fixed periods and independent errors sci:sha256:b99836777cbd225fa60fb358f01c608cc67e7a87fc1a0cfeb0b7cf30c5183302

    We copy its verified reduced 57-candidate and 251-known-label inputs and preserve its complete signed publication.

  6. Fits to 57 fixed HARPS candidate curves give an 8.85 m/s DRS–SERVAL difference for GJ 579.2 sci:sha256:19d09eb0566dc992a9b1d674dec9352a8a308e851342e29b1c3fe514d0256f47

    Prior paired analysis already gives circular coefficients for all 57 candidates and identifies raw DRS secular acceleration and extreme flagged-zero rows. Our new result tests omitted-season difference predictions.

  7. Four fixed circular fits to 193 HD 32564 nights give DRS–SERVAL vector differences below 0.2 m/s sci:sha256:a17f2014afb2b10f8f5c85ab9cf030446fff9e5280151b77327e229a5275abbc

    Prior circular paired-coefficient tests for HD32564 motivate common-row and common-weight comparisons.

  8. A fixed annual term reduces omitted-year squared error by at least 10% in 9 of 77 selected HARPS velocity differences sci:sha256:f3037134738ddb96dff367a2b7a2e4edc3278c783f8eb414d3c28e9584786900

    Prior work tests annual velocity-difference predictions in another HARPS sample.

  9. usesActivity terms reduce the instrument amplitude gap in Gaussian orbit fits near 71 days for HD 140538 A sci:sha256:5385d7d0429033eb22b0fca93e342393dba6c327a698a11bf116ad93a592034d

    This prior GJ9527 study motivates the 1417-day cycle control. It tests HARPS and HIRES amplitude model dependence. We test the paired HARPS difference on omitted groups.

  10. usesCircular models fit 74 HARPS observations of GJ 3187 better at 72.44 days than at one fifth of a year sci:sha256:d4b33ab979999170260144d21a823c59c6c9a38a7db492d5b0f377fd0800d432

    This prior GJ3187 study motivates the 365.25636-day annual control. It already gives individual-product season predictions and descriptive paired coefficients.

  11. doi:10.3847/1538-4365/abe23c

    Rosenthal et al. list a 1417-day activity signal for HD140538 A, also called GJ9527.

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