A precise mass measurement of the intermediate-mass binary pulsar PSR J1802-2124

TL;DR

This paper reports a precise measurement of the masses in the intermediate-mass binary pulsar system PSR J1802-2124, providing insights into its evolution and the characteristics of such systems.

Contribution

It presents the first precise mass measurements of the pulsar and white dwarf in PSR J1802-2124 using Shapiro delay, advancing understanding of IMBP systems.

Findings

Pulsar mass: 1.24 solar masses

White dwarf mass: 0.78 solar masses

System likely underwent a common-envelope phase

Abstract

PSR J1802-2124 is a 12.6-ms pulsar in a 16.8-hour binary orbit with a relatively massive white dwarf (WD) companion. These properties make it a member of the intermediate-mass class of binary pulsar (IMBP) systems. We have been timing this pulsar since its discovery in 2002. Concentrated observations at the Green Bank Telescope, augmented with data from the Parkes and Nancay observatories, have allowed us to determine the general relativistic Shapiro delay. This has yielded pulsar and white dwarf mass measurements of 1.24(11) and 0.78(4) solar masses (68% confidence), respectively. The low mass of the pulsar, the high mass of the WD companion, the short orbital period, and the pulsar spin period may be explained by the system having gone through a common-envelope phase in its evolution. We argue that selection effects may contribute to the relatively small number of known IMBPs.