These images are taken from a computer artist's concept that illustrates a thermonuclear burst enveloping an entire neutron star.
Neutron star EXO 0748-676 (blue sphere) is part of a binary star system, and its neighboring star (yellow-red sphere) supplies the fuel for the thermonuclear bursts. During outbursts of material from the neighboring star, or when the orbit brings the stars closer together, gas from the companion star flows toward the neutron star, attracted by its strong gravity. The flow of gas forms a swirling disk around the neutron star, called an accretion disk (multi-colored swirl around the blue sphere).
Thermonuclear bursts arise as gas moving at close to the speed of light crashes onto the neutron star surface. The dark blue area is the edge of the neutron star, and the mottled, light blue area is the accretion disk, seen face-on.
The gas, pinned to the neutron star by gravity, spreads across the surface. As more and more gas rains down, pressure builds and temperature climbs until there is enough energy for nuclear fusion.
This ignites a chain reaction that engulfs the entire neutron star within a second. Bursts last for one to two minutes and can occur several times per hour.