Gaia DR3 Limits on Stellar Engine Technosignatures in Nearby Stars

Abstract

An operating stellar engine that transfers momentum to its host star could produce an approximately persistent transverse acceleration during the Gaia Data Release 3 (DR3) observing epoch. We ask how common such stellar-engine-like accelerations could be among nearby stars. We define a quality-selected parent population of 406,984 Gaia DR3 stars with nominal distances below 200 pc (about 650 lt-yr) and analyze the 8890 published constant-acceleration (Acceleration7) solutions within this population. Because long-period binaries and astrometric systematics can produce similar sky-plane curvature, we model these conventional explanations together with a broad component that can absorb persistent acceleration or remaining model mismatch. Above a transverse-acceleration threshold of a0 = 2.60 × 10−4 m s−2, where the modeled searchable fraction is essentially unity, the one-sided 95% model-conditional upper limit on the fraction of the parent population allowed to show such accelerations is 1.21 × 10−5—about 12 per million stars in this parent population. At lower acceleration thresholds, the modeled searchable fraction declines, so the corresponding bounds mainly characterize the reach of the search. No individual source is interpreted as a technological signal.