Binary Stellar Companion Hypothesis: Predicted Solar Periodicities Confirmed in Two Independent Datasets

This paper tests the hypothesis that our Sun has a binary stellar companion with an orbital period of approximately 25,772 years — matching Earth's measured precessional cycle. The hypothesis predicts specific harmonic periodicities in solar activity at P/256 = 101.6 years and P/128 = 203.1 years. We test these predictions against two independent datasets: 275 years of SILSO sunspot data (1749–2026) and the Steinhilber et al. (2012) 9,400-year solar activity reconstruction from cosmogenic isotopes. The dominant period in the SILSO record is ~101 years (matching P/256 to within 0.8%). The dominant period in the cosmogenic record is ~208 years (matching P/128 to within 2.4%). Both the Gleissberg cycle and the de Vries/Suess cycle are well-documented but mechanistically unexplained; the binary hypothesis provides a single explanation for both. A two-harmonic model fitted to 23 solar cycle maxima independently finds periods of ~42 and ~104 years. Separately, Gaia DR3 proper motion analysis of 30 million stars shows chi-square = 457 (p < 0.001) anisotropy aligned with the proposed binary corridor axis, surviving secular aberration correction. A falsifiable prediction is presented: Gaia DR4 epoch astrometry (December 2, 2026) should show systematic position drift in the proposed gate stars Elnath and Alpheratz toward the corridor axis, inconsistent with their measured proper motions alone. All data is publicly available and independently reproducible.

Data availability

All data used in this analysis is freely available from public archives without registration. SILSO sunspot data is available at sidc.be/SILSO/datafiles under CC BY-NC license. The Steinhilber 2012 cosmogenic isotope reconstruction is available from NOAA/WDS Paleoclimatology (doi:10.25921/ytyh-f437). Gaia DR3 data is available from the ESA Gaia archive at gea.esac.esa.int/archive. TESS light curve data is available from the MAST archive at mast.stsci.edu. Analysis scripts are available from the author on request.

Ethics

This research involves no human subjects, animal subjects, personally identifiable data, or sensitive materials. All data analyzed is publicly available archival astronomical and paleoclimate data. No ethical review is required or applicable.

Funding

This research received no external funding. All analysis was conducted independently using freely available data and open-source software. No institutional support was received.

Competing interests

The author declares no competing interests. This research was conducted independently with no financial relationships to disclose. The author has no affiliation with the Binary Research Institute or any other organization with a stated position on the binary star hypothesis.