Astronomers from the Leiden Observatory, Netherlands, and the University of Rochester, New York, have discovered a massive ring system obscuring the light of the young star J1407b. It is believed that the rings belong to a massive planet or possibly a brown dwarf, with an orbital period of roughly 10 years. The giant planet boasts a ring system around 200 times larger than that of Saturn, whose own rings were heavily depleted in the act of creating its many moons.
The distant solar system was originally discovered in 2012 by analyzing data from the UK's SuperWASP program, designed to detect gas giants as they move in front of their parent star. At the time, the team noted a number of unusual eclipses that hinted at the presence of a ring system, however the sheer enormity of that system has not been understood until now.
"The details that we see in the light curve are incredible," states Matthew Kenworthy, lead astronomer for the project at Leiden Observatory. "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. 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."
This, combined with the light curve observed when the rings eclipsed the exoplanet's parent star, allowed the team to estimate that the system spanned an incredible 120 million km (74 million miles) in diameter, and contained the equivalent to the mass of Earth in dusty particles. The planet itself is believed to have a mass of 10 to 40 times that of Jupiter.
The materials present in the rings are ripe for the creation of exomoons, and team members believe that they have found at least one clear gap in the structure that would hint at the presence of a moon carving out the distinctive gap. By determining the size of the clear lane present in the ring, astronomers believe that the satellite body may have a mass ranging somewhere between that of Earth and Mars.
However the creation of new moons comes at a cost, and just as was the case with Saturn, the team believes that as the system births more exomoons, that the rings will diminish, and possibly even disappear over a time frame of the next several million years.
Source: University of Rochester