The Evolution of Protoplanetary Disks Around Millisecond Pulsars: The PSR 1257 +12 System

TL;DR

This study models the evolution of protoplanetary disks around millisecond pulsars, specifically PSR 1257+12, showing how different initial conditions and disk models influence planet formation and disk composition.

Contribution

It introduces detailed models of supernova-fallback and tidal disruption disks around pulsars, analyzing their potential to form planets and their evolution over time.

Findings

Supernova-fallback disks can produce material for the three known pulsar planets.

Tidal disruption disks tend to underproduce solids inside 1 AU.

Circumpulsar gas dissipates within 10^5 years, hindering gas giant formation.

Abstract

We model the evolution of protoplanetary disks surrounding millisecond pulsars, using PSR 1257+12 as a test case. Initial conditions were chosen to correspond to initial angular momenta expected for supernova-fallback disks and disks formed from the tidal disruption of a companion star. Models were run under two models for the viscous evolution of disks: fully viscous and layered accretion disk models. Supernova-fallback disks result in a distribution of solids confined to within 1-2 AU and produce the requisite material to form the three known planets surrounding PSR 1257+12. Tidal disruption disks tend to slightly underproduce solids interior to 1 AU, required for forming the pulsar planets, while overproducing the amount of solids where no body, lunar mass or greater, exists. Disks evolving under 'layered' accretion spread somewhat less and deposit a higher column density of solids into the disk. In all cases, circumpulsar gas dissipates on $\lesssim 10^{5}$ year timescales, making formation of gas giant planets highly unlikely.