An Introduction to Modern Astrophysics · Problem 15.15

The Degenerate Remnants of Stars — Carroll & Ostlie

Physics — Astrophysics · electron-positron-annihilation-neutron-star

Problem

Consider an electron and positron that annihilate each other at the surface of a neutron star (

M = 1.4\,M_\odot

R = 10

km), producing two gamma-ray photons of the same energy. Show that each gamma ray has an energy of at least 511 keV.