Saturn's ring system may be impressive but a giant exoplanet dubbed J1407b has rings so massive that they do not only dwarf those of Saturn's. They also blots out up to 95 percent of the light of its host star, J1407.
Astronomers in the Netherlands initially discovered the massive ring system outside of the solar system in 2012 but a new analysis reveals how impressive this ring system is.
For a new study to be published in the Astrophysical Journal, Matthew Kenworthy and his colleagues from the Leiden Observatory in The Netherlands, used data from when the exoplanet passed in front of the system's sun. The oberservations were made during a recent eclipse event that was documented by the SuperWASP project, a survey for detecting gas giants that move in front of their host star.
The researchers were able to study the light emanating from J1407 as it passed behind the massive rings and found something odd. When planets pass in front of the star, there typically occurs a dip in starlight lasting for up to a few hours. In the case of J1407, however, its starlight dimmed for two months.
"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," Kenworthy said. "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."
The astronomers likewise looked at more than 30 rings in the system and found that each ring spans tens of millions of kilometers in diameter easily outsizing the famous rings that circle planet Saturn. They also observed that in between the individual concentric rings are gaps that suggest the presence of exomoons, which are not too different from the shepherd moons of Saturn that keep shaping the planet's rings.
Using adaptive optics, Doppler spectroscopy and findings from earlier studies on the J1407 system, the researchers concluded that J1407 has a yet unseen giant planet , J1407b, with a gigantic ring system. They likewise found evidence suggesting that the diameter of this ring system is almost 120 million kilometers, which is over 200 times larger than Saturn's rings.
"This light curve is interpreted as the transit of a giant ring system that is filling up a fraction of the Hill sphere of an unseen secondary companion, J1407b," the researchers wrote. "This eclipse and model implies that we are seeing a circumplanetary disk undergoing a dynamic transition to an exosatellite-sculpted ring structure and is one of the first seen outside our Solar system."