The impact of close encounters on the evolution of solar system analogs

The Solar System represents a typical debris-disk case, whose long-term evolution can be reconstructed by comparison with analogous systems of different ages. In this work, we analyse the occurrence of stellar flybys among a selected sample of debris-disk-hosting stars, with particular attention to Sun-like objects. Using Gaia DR3 astrometry and a linear approximation of stellar motion, we identify flyby events for 100% of our targets, finding close encounters for about 40% of them. The closest events occur at 0.1–0.2 pc. No dependence on stellar age or mass is observed, suggesting that such encounters are common in the solar neighbourhood. By repeating the analysis on an expanded control catalogue, we recover consistent results, confirming that stellar flybys are a persistent feature of the local Galactic environment. Nevertheless, even the closest separations are orders of magnitude larger than those explored in hydrodynamical simulations, indicating that assessing their dynamical impact requires dedicated modelling. Among the twelve stars with past encounters within 0.3 pc, seven show confirmed infrared excess, which could indicate limited dust exchange or mild disk replenishment. For stars with confirmed planets, the fraction of close encounters decreases to roughly 27% versus 40% for the full catalogue, suggesting that planetary systems may inhabit less dynamically active Galactic regions. For the Sun-like subsample, the same statistics and distance ranges hold, and the Solar System’s flyby is consistent with the overall trend. The Sun ranks within roughly the 10% closest encounters by our adopted metric, confirming its typical behaviour among debris-disk stars. This statistical uniformity becomes evident only when past and future encounters are combined, reflecting the time-symmetric nature of the linear model. No significant age dependence is detected, reinforcing the view that stellar flybys are a constant factor shaping the long-term evolution of debris disks.