Researchers at the University of California, Berkeley, and Clarion University in Pennsylvania said massive disks of gas and dust surrounding all the distant stars -- a signature of exoplanets -- suggests comets are also likely inhabitants of these systems.
"This is sort of the missing link in current planetary formation studies," Berkley astronomer Barry Welsh said. "We see dust disks -- presumably the primordial planet-forming material -- around a whole load of stars, and we see planets, but we don't see much of the stuff in between: the asteroid-like planetesimals and the comets."
The six new exocomet systems were discovered between May 2010 and November 2012 using the 2.1-meter telescope of the McDonald Observatory in Texas.
"Now, I think we have nailed it. These exocomets are more common and easier to detect than people previously thought," Welsh said in a Berkeley release Monday.