X-Ray Image of Comet Hyakutake

The above image of Hyakutake was taken by the ROSAT X-ray observatory. Since x-rays are only generally produced by very energetic processes, most scientists didn't expect to see any x-rays coming from Hyakutake. But some astronomers decided to take a look anyway and were surprised to see that there was copious x-ray production near comet Hyakutake. As seen above, the emission is not centered on the nucleus, which is the center of most other cometary phenomena, but is offset by about 30,000 miles. We still don't understand what is producing these x-rays near Hyakutake, but searches of the ROSAT archives have revealed that x-ray emission was also detected during previous observations of four other comets. (ROSAT has been performing an all-sky survey in x-rays and occasionally ``accidently'' scans across the path of a comet.)

Credit: Casey Lisse, University of Maryland, and his observing team