Neutron star kicks plus rockets as a mechanism for forming wide low-eccentricity neutron star binaries

TL;DR

This paper proposes that prolonged rocket-like accelerations combined with natal kicks can form wide, low-eccentricity neutron star binaries and induce stellar mergers, explaining observed systems and transient phenomena.

Contribution

It introduces a novel mechanism involving combined rocket-like and natal kicks for neutron star binary formation and post-supernova mergers.

Findings

Combined rocket and natal kicks enable new binary configurations.

Proposed mechanism explains observed wide, low-eccentricity binaries.

Induces stellar mergers leading to high-energy transients.

Abstract

Recent neutron star surface observations corroborate a long-standing theory that neutron stars may be accelerated over extended periods after their birth. We analyze how these prolonged rocket-like accelerations, combined with rapid birth kicks, impact binary orbits. We find that even a small contribution of rocket kicks combined with instantaneous natal kicks can allow binaries to reach period--eccentricity combinations unattainable in standard binary evolution models. We propose these kick + rocket combinations as a new channel to form wide low-eccentricity neutron star binaries such as Gaia NS1, as well as inducing stellar mergers months to years after a supernova to cause peculiar high-energy transients.