Millisecond Pulsars, their Evolution and Applications

TL;DR

Millisecond pulsars are rapidly spinning neutron stars with unique evolutionary paths, highly stable periods, and diverse applications in astrophysics, including gravitational tests, planetary detection, and understanding stellar evolution.

Contribution

This paper reviews the properties, evolution, and multifaceted applications of millisecond pulsars, highlighting recent insights into their physics and astrophysical significance.

Findings

MSPs have stable periods suitable for precise astrophysical measurements.

They are used to test gravitational theories and detect gravitational waves.

Transitioning MSPs provide insights into accretion physics.

Abstract

Millisecond pulsars (MSPs) are short-period pulsars that are distinguished from "normal" pulsars, not only by their short period, but also by their very small spin-down rates and high probability of being in a binary system. These properties are consistent with MSPs having a different evolutionary history to normal pulsars, viz., neutron-star formation in an evolving binary system and spin-up due to accretion from the binary companion. Their very stable periods make MSPs nearly ideal probes of a wide variety of astrophysical phenomena. For example, they have been used to detect planets around pulsars, to test the accuracy of gravitational theories, to set limits on the low-frequency gravitational-wave background in the Universe, and to establish pulsar-based timescales that rival the best atomic-clock timescales in long-term stability. MSPs also provide a window into stellar and binary evolution, often suggesting exotic pathways to the observed systems. The X-ray accretion-powered MSPs, and especially those that transition between an accreting X-ray MSP and a non-accreting radio MSP, give important insight into the physics of accretion on to highly magnetised neutron stars.