Stellar encounters in the solar neighbourhood and the special case of GJ 710

¹ Institut de Ciències de l’Espai (ICE, CSIC), Campus UAB, C/ Can Magrans s/n, 08193 Bellaterra, Spain
² Institut d’Estudis Espacials de Catalunya (IEEC), C/Esteve Terradas, 1, Edifici RDIT, Campus PMT-UPC, 08860 Castelldefels (Barcelona), Spain
³ Institute of Astronomy, University of Cambridge, Madingley Rd, Cambridge CB3 0HA, UK
⁴ Dept. Ingeniería Energética, Universidad Nacional de Educación a Distancia (UNED), C/ Juan del Rosal 12, 28040 Madrid, Spain

^★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 18 February 2026
Accepted: 23 April 2026

Abstract

Aims. We present a comprehensive characterisation of close stellar encounters in the solar vicinity, with a particular focus on placing the predicted fly-by of GJ 710 in context. This star will come extremely close (0.0621 pc or ∼10⁴ AU) to the Solar System in approximately 1.3 Myr.

Methods. Using a linear motion approximation, we identified past and future close stellar encounters within 1 pc of the Solar System, using a complete sample of nearby stars. We assessed the completeness of our dataset and applied corrections to the radial velocities, accounting for gravitational redshift and convective blueshift. Such effects can bias the measured velocities and affect the derived encounter parameters. Furthermore, we computed close encounters for all the stars in the Solar System vicinity to build a statistically significant sample of such events. We accounted for binary systems and common proper motion pairs, applying corrections to account for incompleteness at the edges of our time window.

Results. We derived reliable statistics for close stellar encounters of stars within 25 pc of the Sun. We report a rate of encounters within 1 pc and within 0.47 Myr of 10.6 ± 4.5 per Myr and star, implying an average of one encounter every 95₋₂₈⁺⁷¹ kyr. Additionally, from the resulting distribution, we can evaluate the relative frequency of the upcoming GJ 710 fly-by, which is found to be quite rare, at a rate of one per ∼50 Myr.

Conclusions. This work provides new insights into the dynamic environment of the solar neighbourhood by quantifying the rates and distributions of close stellar encounter events.