White dwarf pollution in wide binaries: the role of planetary mass

Abstract

Atmospheric pollution in white dwarfs is interpreted as evidence for the accretion of rocky material from remnant planetary systems. In wide binaries, these reservoirs can be influenced by planetary perturbers. Here, we investigate how planetary mass affects the survival and delivery of planetesimals onto an evolving white dwarf. We perform N-body simulations incorporating time-dependent stellar evolution and a stellar companion, varying planetary masses and following the evolution of a planetesimal disc. We find that lower-mass planets perturb the planetesimal reservoir less efficiently, allowing more planetesimals to survive longer. Consequently, delivery onto the white dwarf can persist into the cool white dwarf phase, whereas high-mass planets deplete the reservoir earlier, preventing sustained pollution at late stages. Our results show that planetary mass regulates the timescale over which rocky material remains available for accretion, while the planet's location has minor impact. Pollution is more frequent in binaries with lower inclinations and eccentricities.