This is an image of a 'classical nova'. Sounds boring, right? Not when you describe it as "an outburst produced by a thermonuclear explosion on the surface of a white dwarf star", it's not.

It's a composite image of GK Persei, a famous astronomical phenomenon that first became famous in 1901. GK Persei is a 'classical nova', the smaller sister of a supernova:

A nova can occur if the strong gravity of a white dwarf pulls material from its orbiting companion star. If enough material, mostly in the form of hydrogen gas, accumulates on the surface of the white dwarf, nuclear fusion reactions can occur and intensify, culminating into a cosmic-sized hydrogen bomb blast. The outer layers of the white dwarf are blown away, producing a nova outburst that can be observed for a period of months to years as the material expands into space.

This new image of GK Persei contains X-rays from Chandra (blue), optical data from NASA's Hubble Space Telescope (yellow), and radio data from the National Science Foundation's Very Large Array (pink). The X-ray data show hot gas and the radio data show emission from electrons that have been accelerated to high energies by the nova shock wave. The optical data reveal clumps of material that were ejected in the explosion. The nature of the point-like source on the lower left is unknown.

The study of novas is scientifically relevant on its own — they can tell us a great deal about cosmic explosions, thanks to the smaller scale than supernovas — but honestly, anything this beautiful is worth studying all on its own. [NASA]