J1407b, a young exoplanet, has a massive ring system that is much heavier and 200 times larger than Saturn’s rings. Astronomers discovered the giant planet, which could be a brown dwarf (a failed star), when it eclipsed J1407, a very young sun-like star. This ring system, the first of its kind discovered outside of the solar system, consists of at least 30 rings, each measuring tens of millions of kilometers in diameter.
“You could think of it as kind of a super Saturn,” University of Rochester’s Eric Mamajek says in a news release. The star and its unusual eclipses were discovered in 2012 by Mamajek’s team using data from a survey designed to detect gas giants moving in front of their parent star. Using adaptive optics and Doppler spectroscopy, a team led by Matthew Kenworthy of the Netherlands’ Leiden Observatory discovered that the repeated dimming of J1407’s starlight was caused by a giant planet with a massive ring system. The findings will be published in The Astrophysical Journal.
“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 explains. While the star is too far for researchers to observe the rings directly, the team was able to make a model using the rapid variations in brightness of starlight passing through the rings.
“This planet is much larger than Jupiter or Saturn, and its ring system is roughly 200 times larger than Saturn’s rings are today. You could think of it as kind of a super Saturn”, Erik Mamajek said.
The disk of rings is so vast that, were it around Saturn, it would dominate our night sky, the astronomers said. According to Matthew Kenworthy of the Leiden Observatory in The Netherlands:
“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.”
Mamajek put into context how much material is contained in these disks and rings:
“If you were to grind up the four large Galilean moons of Jupiter into dust and ice and spread out the material over their orbits in a ring around Jupiter, the ring would be so opaque to light that a distant observer that saw the ring pass in front of the sun would see a very deep, multi-day eclipse.”
“In the case of J1407, we see the rings blocking as much as 95 percent of the light of this young Sun-like star for days, so there is a lot of material there that could then form satellites.”
Astronomers expect that the rings will become thinner in the next several million years and eventually disappear as satellites form from the material in the disks.
Bottom line: First-ever ringed planet beyond our solar system. You could think of it as kind of a super Saturn. Called J1407b, its ring system is 200 times larger than Saturn’s.
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