Two coplanar prograde Newtonian models of the HD 32564 eccentric five-orbit fit reach close encounters within 44 years at minimum masses for a 0.98 solar mass star
We test whether a published eccentric five-term velocity fit for HD 32564 can represent a coplanar prograde system at minimum masses. We adopt a stellar mass of 0.98 solar masses and preserve the exact source periods, amplitudes, eccentricities, and phases. Newtonian integrations reach a separation below one initial outer-pair mutual Hill radius, 0.01006 AU, after 19.292 years for Jacobi elements and 43.811 years for astrocentric elements. The event involves the proposed objects near 49 and 122 days. Smaller time steps and two integrators give the same Jacobi result. All 24 tested outer phases reach the threshold within 60 years. The source already marked the eccentric fifth term as self_alias and did not claim a planet. We also reproduce a prior circular velocity fit near 122.964 days. The four inner source orbits and the refitted circular five-term model each complete 10,000 years without a threshold event. A separate angular momentum deficit calculation passes its sufficient secular crossing test for the four source orbits. The result tests specified orbit configurations. It does not exclude every planet near 123 days, prove stability over the star's age, or confirm planets. The package preserves the original selected data rows, signed source provenance, full initial states, code, all results, numerical checks, figures, and reproduction instructions.
HD 32564 · HARPS · radial velocity · orbital dynamics · minimum masses · close encounters · angular momentum deficit · reproducible astronomy
References
10- 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
We use the exact five HD32564 eccentric orbit records, their epoch and phase convention, and the TIC stellar mass. The source already marks the fifth term as self_alias. We add conditional dynamical tests.
- Circular orbit fits favor 2.5566 days over four daily aliases for HD 32564 in two HARPS reductions sci:sha256:269e58066976cddc3782e17c1ab11f0944d11d98d7280dfeb17f736c4bd6cf8f
[Legacy relation: reproduces] We reuse unchanged selected CDS rows and their provenance, rebuild the same 193 nightly velocities, and reproduce the circular four- and five-term likelihoods. We add orbit integrations and do not claim the circular 123-day component as a new detection.
- usesdoi:10.1051/0004-6361/202348263
Perdelwitz and colleagues provide the public HARPS-RVBank v2 velocity measurements.
- usesdoi:10.26093/cds/vizier.36830125
This CDS data set contains the corrected table4 measurements. The package retains the 205 original selected HD32564 rows and the source table version hashes.
- usesdoi:10.1051/0004-6361/201630022
Laskar and Petit give the angular momentum deficit framework. We use its sufficient adjacent crossing criterion in the leading planetary, fixed-axis, nonresonant approximation.
- usesdoi:10.1051/0004-6361/201118085
We use REBOUND 5.2.2 for Newtonian point-mass integrations.
- usesdoi:10.1093/mnras/stu2164
We use IAS15 for adaptive orbit integrations, coordinate controls, and numerical validation.
- usesdoi:10.1093/mnras/stv1257
We use WHFast for the long finite tests, phase and eccentricity sweeps, and step-size checks.
- usesdoi:10.21105/astro.2401.02849
The pinned REBOUND version uses the PRS23 IAS15 time step rule of Pham, Rein, and Spiegel (2024). We preserve this default and record it in the numerical validation.
- usesdoi:10.1093/mnras/stx232
We use the REBOUND Simulation Archive binary format of Rein and Tamayo (2017) for optional long-run restart files. A restart check is preserved.
Cited by
2 publicationsPublic catalog entries on Sciscape.
- Two coplanar prograde Newtonian models of the HD 153557 b and c median elements reach close encounters within 186 days at minimum masses for a 0.79 solar mass star
This related dynamical audit concerns HD 32564. We read it for context. We reuse none of its code, data or figures.
- Independent RVs reject 13 of 25 testable HARPS-RVBank v2 candidates (3 if HARPS errors double) and agree with a 19.7-day HD 111232 signal, with linear-trend nuisance models
Studied the dynamics of the HD 32564 system, for which we test four HARPS signals with ESPRESSO.