Rings of Super Saturn — The planet with rings 200 times larger than Saturn’s

The what and how of the largest planetary ring system ever found

About 420 light years away lies a very young planet around a very young sun-like star, with Saturn like rings around it. What is not like Saturn is the truly colossal size of the rings. Transit observations revealed that this gas giant planet has rings 200 times larger than the rings of Saturn. And so the title of the Lord of the Rings goes to J1407b — a Super Saturn at least 20 times more massive than Saturn itself.

Artist’s conception of the giant ring system of the planet J1407b. Source: Rochester

Here is how the planet’s ring system size compares to its sun:

To scale size comparison of planet J1407b and its rings (left) to its sun (right). Source: CTIO NOAO

The large ring system was discovered due to it deeply eclipsing the planet’s sun for weeks. The rings have a lot of material in it (containing the mass of an entire Earth), which block the light of the planet’s sun. Here is a video showing the drop in the star’s brightness during the ring-eclipse.

Drop in the star’s brightness explained by the modeled rings of the planet J1407b. Source: Matthew Kenworthy

Extending ~180 million km in length, the size of the rings beat the Earth-Sun distance. The question is how do such large rings even exist when they should be torn apart by the gravity of the planet’s sun.

An interesting way this was solved was proposing that the rings were spinning in the opposite direction to that of its planet around its sun. This means that the particles that make up the ring system are never too close to the sun for too long, and thus can stay together in a ring formation in the face of the star’s intense gravitational pull. Here’s an animation.

A simulation of rings spinning in the opposite direction of the planet J1407b (left) vs. in the same direction (right). Source: Steven Rieder on Vimeo

The rings stay intact when spinning counter-clockwise as opposed to clockwise spinning with respect to the planet’s spin, hence solving the mystery. Now the question is how do you get rings spinning in the opposite direction in the first place? Well, more answers to find out for Science.

There is another interesting thing about these rings. Did you notice the ring gap in the above video at 0:09?

Since the gap is quite substantial and the planetary system quite young, it is thought that the gap in the rings is cause by a newly formed moon up to 80% the mass of Earth. What we are seeing here is a Jupiter/Saturn like vast moon system being formed. Only larger.

After the 13 years of stunning Saturn Science that NASA’s Cassini spacecraft has given us, one can only imagine the beautiful imagery and intricate data that will be revealed when (and if) we send a spacecraft to this Lord of the Rings. Meanwhile here’s a simulated version.

J1407b transit seen from its moon, simulated in Celestia. Source: Wikipedia

Dreamy. Just to think that there are such extreme worlds out there in the Universe waiting to be discovered, simply boggles my mind.


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