White dwarf pollution in wide binaries I: the effects of stellar evolution

Résumé : Context. Atmospheric pollution in white dwarfs is interpreted as evidence for the accretion of rocky material from remnant planetary systems. Wide binary companions can influence the delivery of planetary material onto white dwarfs, making it essential to understand the interplay between stellar evolution and binary perturbations. Aims. We investigate how uncertainties in stellar mass-loss histories affect the dynamical evolution of remnant planetary systems in wide binaries, and assess their relative importance compared with binary perturbations in driving the accretion of rocky material onto white dwarfs. Methods. We perform REBOUND N-body simulations incorporating time-dependent stellar parameters interpolated from MESA evolutionary tracks and tidal interactions, following the dynamical evolution up to the white dwarf stage. We explore two stellar-evolution models with distinct mass-loss histories for wide binary systems hosting a Jupiter-mass planet and a planetesimal disc, spanning a range of binary architectures. Results. The adopted stellar-evolution model has only a minor effect on the survival of the planet, mainly affecting the timing and efficiency of planetesimal delivery during the white dwarf stage. Instead, the architecture of the binary primarily controls the pollution outcome: wider binaries produce the highest rates of accretion onto the white dwarf, consistent with the observed prevalence of polluted white dwarfs in wide binaries. Moreover, planetesimal reservoirs remain long-lived, with survival times increasing with binary separation, enabling Gyr-long metal pollution. Conclusions. Our results suggest that the architecture of wide binaries, rather than uncertainties in stellar evolution, is the dominant factor controlling the dynamical delivery of rocky material onto white dwarfs.