The Japanese professors and their team calculated that the accretion disks of black holes could be home to astonishingly large planetary systems. These accretion disks of supermassive black holes contain the material of a hundred thousand Suns and some parts of the disk could be shielded from hostile radiation.
The paper speculates that tens of thousands of planets with ten times the mass of the Earth could be formed around ten light-years from a black hole:
"Our calculations show that tens of thousands of planets with ten times the mass of the Earth could be formed around ten light-years from a black hole," said Eiichiro Kokubo, co-author of the paper and a professor at the National Astronomical Observatory of Japan. The process is much slower than in traditional protoplanetary disks, however, and could take up to several hundred million years instead of just tens of millions of years.More details The Register. At the moment, it's not possible to verify the simulations as there is no known method to study black holes.
“Around black holes there might exist planetary systems of astonishing scale," Kokubo added.