A Fallback Disk Accretion-Involved Formation Channel to PSR J1903+0327

TL;DR

This paper proposes a new formation channel for PSR J1903+0327 involving fallback disk accretion during supernova, which can produce eccentric millisecond pulsars with specific magnetic fields, supported by population synthesis.

Contribution

It introduces a fallback disk accretion scenario for forming eccentric millisecond pulsars, a process not previously detailed for such systems.

Findings

Population synthesis suggests tens to hundreds of similar systems in the Galaxy.

Fallback disk accretion can spin up neutron stars to millisecond periods.

Eccentric orbits can be maintained for about 1 billion years after supernova.

Abstract

The discovery of the eccentric binary and millisecond pulsar PSR J1903+03273 has raised interesting questions about the formation mechanisms of this peculiar system. Here we present a born-fast scenario for PSR J1903+03273. We assume that during the supernova (SN) explosion that produced the pulsar, a fallback disk was formed around and accreted onto the newborn neutron star. Mass accretion could accelerate the neutron star's spin to milliseconds, and decrease its magnetic field to $\sim 10^8-10^9$ G, provided that there was sufficient mass ($\sim 0.1 M_{\sun}$) in the fallback disk. The neutron star became a millisecond pulsar after mass accretion terminated. In the meanwhile the binary orbit has kept to be eccentric (due to the SN explosion) for $\sim 10^{9}$ yr. We have performed population synthesis calculations of the evolutions of neutron stars with a fallback disk, and found that there might be tens to hundreds of PSR J1903+03273-like systems in the Galaxy. This scenario also suggests that some fraction of isolated millisecond pulsars in the Galactic disk could be formed through the same channel.