​This Exoplanet's Rings Are 200 Times Larger Than Saturn’s

Astronomers have successfully imaged a planet with a ring system so massive, it blots out 95 percent of its host star's light. The results of a detailed survey of the planet, known as J1407b, were announced today, and will be featured in a forthcoming edition of The Astrophysical Journal.

"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," study co-author Eric Mamajek said in a statement.

"However, until we discovered this object in 2012, no-one had seen such a ring system," he continued. "This is the first snapshot of satellite formation on million-kilometer scales around a substellar object."

Mamajek and his colleagues estimate that J1407b is about 10 to 40 times the size of Jupiter, with rings 200 times as massive as those in Saturn's system. In fact, it's so big that some astronomers haven't ruled out the possibility that it may be a brown dwarf star.

Regardless, this monster orb, located about 42 light years from our solar system, regularly eclipses its young Sun-like host star. This gave the Rochester a spectacular backlit glimpse of its extensive ring system, which contains 30 substructures with a diameter of about 120 million kilometers. That's the equivalent of 10,000 Earth diameters, or 80 percent of the distance between the Earth and the Sun.

Computer model of light curve of the star J1407 seen in SuperWASP data in 2007. Credit: Matthew Kenworthy/Vimeo.

The team imaged the hulking ring system using the SuperWASP survey, which consists of two robotic observatories that specialize in rooting out extrasolar gas giants. The researchers imaged J1407b's light curve—the measure of an object's luminosity over time—as it passed in front of its star. From there, they were able to characterize the size, mass, and structure of its unusual rings, and even provided compelling evidence that the gaps in the rings are caused by developing exomoons.

"The details that we see in the light curve are incredible," said lead author Matthew Kenworthy of Leiden Observatory in a statement. "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."

"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," he added.

While I don't want to give Saturn an inferiority complex, it is amazing to imagine this stunning object upstaging the Moon in the night sky. It has definitely earned a place on the list of exoplanets that deserve their own fictional tourism board advertisement.