This picture shows a small extract of one of the X-ray images shot by the EPIC cameras on board ESA's XMM-Newton for the Taurus-Auriga survey project. The bright star on the left is one of many normal, young, solar-like stars in the Taurus-Aurigae star-formation region. It shows bright X-rays from very hot gas. The star to its right is AB Aurigae.
The image has been color-coded, and the orange color shows that the gas of AB Aurigae is much cooler than that in the other young stars.
The insert on the right (light-curve) shows how the X-ray intensity moved cyclically up and down with a period of about 42 hours.