J1407b is the infamous gas giant with a gargantuan ring system. Located 420 light-years away from Earth, the planet possesses one of the largest known rings systems in the galaxy, with a diameter of about 0.6 AU (reliant on the definition of the ring) or well over 15% its semi-major axis.
J1407b was first discovered by human astronomers from the University of Rochester on 2012. Due to its size, some theories arose that it was not a ´´planet´´, but a tiny brown dwarf. It was not until the year 2015 when a scientific expedition was sent to the planet, that the issue was resolved.
The rings consists of dust particles which comes from the initial halo around the parent star, which were captured by the planet's gravity before it could accrete into proper planets. In fact, accretion process continues within the ring system. From the initial establishment of human presence 7,600 years ago, several newly formed moons have been noted, with frequent impact between these bodies. This have made J1407b an extremely interesting subject of study amongst astronomers.
For safety and scientific reasons, both the URSS and the Confederacy of Humanity had prohibited any mining or construction activities within the system, utilizing it as a massive scientific laboratory. Dozens of research outposts have been established in orbits around the planet by universities. The gravitational engineering technology, most famously utilized in Sol System to place Mercury into Venerean orbit and to capture Vulcan, was partially developed from the scientific findings from J1407b.
As of year 10,000, the largest satellite spotted around J1407b i.e. J1407b-I is a rocky body with a mass of about three times that of Luna, but its orbit and physical properties are not properly documented due to the frequent impact events and gravitational perturbations. Accretion around the planet is not expected to be complete for the next three million years, even according to the most "optimistic" models.
It is possible that it is just a mount of rings instead of a planet.