Veteran astrophotographer Peter Rosen has been monitoring Comet Pan-STARRS, and his latest images obtained on March 15th seem to show a fragment emerging from the nucleus. It is the speck just below and to the right of the comet's head:
Comet Pan-Starrs
© Peter Rosen
"It is visible also in two or three other image stacks," says Rosen. He notes how the stars in the image are trailed, but the apparent fragment is not. "It seems to follow the comet, not the stars. A plane passed through the field of view during the exposure, making a red streak through the comet's tail."

"The colorful image is a frequency modulation that increases the contrast and clearly shows the fragment as a dark dot below the nucleus," he continues. "I hope this splitting can be confirmed or refuted soon by other observers."

For casual sky watchers: A growing number of people are reporting that they can see Comet Pan-STARRS with the naked eye. Best estimates place the magnitude of the comet at +0.2, about twice as bright as a 1st magnitude star. As the comet moves away from the sun, its visibility is improving, which means you might be able to see it in the nights ahead. Step outside about an hour after sunset and look west: sky map.