Orbital evolution with white-dwarf kicks

TL;DR

This paper explores how asymmetric mass loss during the giant phase can impart velocity kicks to white dwarfs, significantly affecting their orbital evolution and potentially leading to system disruption.

Contribution

It introduces a model for white dwarf kicks due to asymmetric mass loss and analyzes their impact on binary and planetary system dynamics.

Findings

White dwarf kicks can significantly alter orbital eccentricities.

Large kicks may disrupt binary or planetary systems.

Eccentricities can reach order unity due to kicks.

Abstract

Recent observations of white dwarfs in globular clusters indicate that these stars may get a velocity kick during their time as giants. This velocity kick could originate naturally if the mass loss while on the asymptotic giant branch is slightly asymmetric. If white dwarfs get a kick comparable to the orbital velocity of the binary, the initial Runge-Lenz vector (eccentricity vector) of the orbit is damped to be replaced by a component pointing toward the cross product of the initial angular momentum and the force. The final eccentricity may be of order unity and if the kick is sufficiently large, the system may be disrupted. These results may have important ramifications for the evolution of binary stars and planetary systems