Neutron stars and planet-mass companions

Abstract

We propose a formation mechanism for the recently discovered planet-mass companions to neutron stars, namely that the stellar companion of a millisecond pulsar is disrupted by rapid mass loss via an evaporative wind driven by the pulsar radiation. Because the star loses mass on a time-scale short compared to its thermal time-scale, it expands and overspills its Roche lobe. This process can result in the disruption of the stellar companion and the formation of a massive disc around the neutron star. This disc then evolves, in a manner analogous to the solar nebula, to form planet-mass objects around the neutron star.