This article is more than 1 year old

Excitement in boffinry circles as GIGANTIC ALIEN RING BLOTS OUT SUN

Faraway sun J1407b, but you get the idea

Pics The first planetary ring system outside of our Solar System has been spotted and it's massive – in fact, it's 120 million kilometers in diameter.

"This planet is much larger than Jupiter or Saturn, and its ring system is roughly 200 times larger than Saturn's rings are today," said Eric Mamajek, professor of physics and astronomy at the University of Rochester in New York.

"You could think of it as kind of a super Saturn."

The extent of the ring system surrounding the planet was discovered [PDF] by noting the eclipsing effect it had on a very young star dubbed J1407b, which is slightly smaller than our own sun. As the planet moved between observers on Earth and J1407b, light coming from the small star varied, giving the US and Dutch scientific team a good read on the alien world's structure.

There are at least 30 separate rings, we're told, some of which are tens of millions of kilometers wide. The mass of the ring system is roughly equivalent to the total mass of Earth, if our world was ground up small and put into orbit around the unnamed, faraway giant planet.

New planetary rings seen from Earth

If the giant ring system was around Saturn it would dominate the sky here on Earth (artist's impression)

"The details that we see in the light curve are incredible. The eclipse lasted for several weeks, but you see rapid changes on time scales of tens of minutes as a result of fine structures in the rings," said Matthew Kenworthy from the University of Leiden in the Netherlands.

"The star is much too far away to observe the rings directly, but we could make a detailed model based on the rapid brightness variations in the star light passing through the ring system. If we could replace Saturn's rings with the rings around J1407b, they would be easily visible at night and be many times larger than the full moon."

There were gaps in the ring system, however. It appears as though some of the matter has glommed into a moon probably between the Earth and Mars in size. Astronomers have speculated that Jupiter once had a similar disc of matter that accreted into moons, and that many of Saturn's 62 moons were formed in the same way. ®

More about


Send us news

Other stories you might like