A distant exoplanet has rings like Saturn -- well, not like Saturn, exactly, because this planet's rings are so huge and opaque as to make Saturn's look puny, astronomers say.
The rings are somewhat like Saturn's only 200 times as big, and the planet that owns them is somewhere between ten and 40 times the size of Jupiter, the largest planet in our solar system.
If those rings were put in our solar system, they would reach all the way from the sun out to the orbit of Earth, at 93 million miles distance.
Eric Mamajek, a professor of astronomy and physics at the University of Rochester and a co-author of a published study on the planet, says they detected the ringed planet when it eclipsed its own star.
During the eclipse, the star's light dimmed and brightened many time quite rapidly, suggesting an intricate system of rings -- perhaps as many as 30 -- of different sizes with discernable gaps in between, he says.
At least one of those gaps has very clear definition, suggesting a moon has formed out of the rings' material and is orbiting the planet along with the ring system.
"The planetary science community has theorized for decades that planets like Jupiter and Saturn would have had, at an early stage, disks around them that then led to the formation of satellites," Mamajek says. "However, until we discovered this object in 2012, no-one had seen such a ring system. This is the first snapshot of satellite formation on million-kilometer scales around a substellar object."
If the exoplanet ring system were to be put around Saturn, it would be visible from Earth and would be many times larger than the full moon, says study co-author Matthew Kenworth from the Leiden Observatory in the Netherlands.
The ring system probably contains as much as an Earth's worth of mass in its light-obscuring dust particles, the researchers surmise.
The ringed planet's parent star is probably quite young, they say, around 16 million years old compared to our sun's 4.6-billion-year age.
The huge ring system is likely get smaller with time as the outer bands of the young system continue to condense into new moons, they predict.
"That's what you see in [our] Solar System," says Kenworth. "You have rings tucked in close to the planets and moons further out. So presumably we're seeing the intermediate step."
