# Investigation of the asteroid-neutron star collision model for the repeating fast radio bursts

## TL;DR

This study models asteroid-neutron star collisions as a source of repeating fast radio bursts, finding that unrealistically dense debris belts are required to match observed FRB rates, challenging this model's viability.

## Contribution

The paper uses N-body simulations to critically evaluate the asteroid collision model for FRBs, revealing density requirements that are much higher than known debris belts.

## Key findings

- Debris belt density must be at least 10^3 to 10^4 times that of the Kuiper belt.
- Most comets are scattered away during neutron star approach, not accreted.
- Collision rates are insufficient to explain observed FRB frequency without extreme assumptions.

## Abstract

The origin of fast radio bursts (FRBs) is still a mystery. One model proposed to interpret the only known repeating object, FRB 121102, is that the radio emission is generated from asteroids colliding with a highly magnetized neutron star (NS). With N-body simulations, we model a debris disc around a central star with an eccentric orbit intruding NS. As the NS approaches the first periastron passage, most of the comets are scattered away rather than being accreted by the NS. To match the observed FRB rate, the debris belt would have to be at least three orders of magnitude more dense than the Kuiper belt. We also consider the rate of collisions on to the central object but find that the density of the debris belt must be at least four orders of magnitude more dense than the Kuiper belt. These discrepancies in the density arise even if (1) one introduces a Kuiper-belt like comet belt rather than an asteroid belt and assume that comet impacts can also make FRBs; (2) the NS moves 2 orders of magnitude slower than their normal proper-motion velocity due to supernova kicks; and (3) the NS orbit is coplanar to the debris belt, which provides the highest rate of collisions.