# B-ducted Heating of Black Widow Companions

## TL;DR

This paper introduces an intrabinary shock heating model for black widow pulsar companions, explaining observed asymmetries and temperatures better than direct radiative heating, with implications for system mass estimates.

## Contribution

It presents a novel IBS-B model where pulsar wind-induced shocks heat companions, improving light curve fits and understanding of system properties.

## Key findings

- The IBS-B model fits observed light curves more accurately.
- Heating patterns depend on magnetic field and shock geometry.
- Implications for mass estimates of binary systems.

## Abstract

The companions of evaporating binary pulsars (black widows and related systems) show optical emission suggesting strong heating. In a number of cases large observed temperatures and asymmetries are inconsistent with direct radiative heating for the observed pulsar spindown power and expected distance. Here we describe a heating model in which the pulsar wind sets up an intrabinary shock (IBS) against the companion wind and magnetic field, and a portion of the shock particles duct along this field to the companion magnetic poles. We show that a variety of heating patterns, and improved fits to the observed light curves, can be obtained at expected pulsar distances and luminosities, at the expense of a handful of model parameters. We test this `IBS-B' model against three well observed binaries and comment on the implications for system masses.