X-ray emission from the B-type star Xi1 Canis Majoris (Xi1 CMa) – seen in the center of this image - has been measured using ESA's XMM-Newton observatory.
Xi1 CMa was observed continuously with XMM-Newton in October 2012 for almost 29 hours. These observations resulted in the first detection of pulsed X-ray emission from a non-degenerate, massive star.
Xi1 CMa is an extremely bright star with a surface temperature of approximately 27,500K, and a mass of approximately 15 times that of the Sun. It lies some 1400 light years away in the constellation Canis Major. The star has a notably strong magnetic field, about 5000 times stronger than our Sun's.
This 3-colour image of the field was made by mapping 0.2-1.0 keV emission to red, 1.0-2.5 keV emission to green, and 2.5-10.0 keV emission to blue. The field of view of this image is 19 arcmin × 19 arcmin (approximately 7.6 light years × 7.6 light years).
Image credit: ESA/XMM-Newton/L. Oskinova (University of Potsdam)
Note: For more information, see Pulsating X-Rays Allow XMM-Newton to Unmask a Mysterious Star.