Towards a theory of extremely intermittent pulsars I: Does something orbits PSR B1931 + 24 ?

TL;DR

This paper investigates whether an orbiting companion could explain the peculiar intermittent activity of pulsar PSR B1931+24, but concludes that such a companion cannot account for all observed properties.

Contribution

The study systematically evaluates various companion orbit scenarios and interactions, ultimately ruling out the companion hypothesis for PSR B1931+24's behavior.

Findings

Companion orbiting with 35 or 70 days cannot explain pulsar's properties.

No configuration of a companion explains the pulsar's intermittent activity.

Alternative explanations are needed for PSR B1931+24's behavior.

Abstract

We investigate whether one or many companions are orbiting the extremely intermittent pulsar PSR B1931+24. We constrained our analysis on previous observations of eight fundamental properties of PSR B1931+24. The most puzzling properties are the intermittent nature of the pulsar's activity, with active and quiet phases that alternate quasi-periodically; the variation of the slowing-down rate of its period between active and quiet phases; and because there are no timing residuals, it is highly unlikely that the pulsar has a massive companion. Here, we examine the effects that one putative companion immersed in the magnetospheric plasma or the wind of the pulsar might have, as well as the associated electric current distribution. We analysed several possibilities for the distance and orbit of this hypothetical companion and the nature of its interaction with the neutron star. We show that if the quasi-periodic behaviour of PSR B1931+24 was caused by a companion orbiting the star with a period of 35 or 70 days, the radio emissions, usually considered to be those of the pulsar would in that specific case be emitted in the companion's environment. We analysed four possible configurations and conclude that none of them would explain the whole set of peculiar properties of PSR 1931+24. We furthermore considered a period 70 days for the precession of the periastron associated to an orbit very close to the neutron star. This hypothesis is analysed in a companion paper.