Planet Formation around Super Massive Black Holes in the Active Galactic
  Nuclei
  As a natural consequence of the elementary processes of dust growth, we
discovered that a new class of planets can be formed around supermassive black
holes (SMBHs). We investigated a growth path from sub-micron sized icy dust
monomers to Earth-sized bodies outside the "snow line", located several parsecs
from SMBHs in low luminosity active galactic nuclei (AGNs). In contrast to
protoplanetary disks, the "radial drift barrier" does not prevent the formation
of planetesimals. In the early phase of the evolution, low collision velocity
between dust particles promotes sticking; therefore, the internal density of
the dust aggregates decreases with growth. When the porous aggregate's size
reaches 0.1--1 cm, the collisional compression becomes effective, and the
decrease in internal density stops. Once 10--100 m sized aggregates are formed,
they are decoupled from gas turbulence, and the aggregate layer becomes
gravitationally unstable, leading to the formation of planets by the
fragmentation of the layer, with ten times the mass of the earth. The growth
time scale depends on the turbulent strength of the circumnuclear disk and the
black hole mass $M_{BH}$, and it is comparable to the AGN's lifetime ($\sim
10^8$ yr) for low mass ($M_{BH} \sim 10^6 M_\odot$) SMBHs.
