  Top-shaped asteroids have been observed among near-Earth asteroids. About
half of them are reported to have moons (on the order of $\sim 1$wt.\% of the
top-shaped primary) and many of them have an equatorial ridge. A recent study
has shown that the enigmatic top-shaped figure of asteroids (e.g., Ryugu,
Bennu, and Didymos) could result from an axisymmetric landslide of the primary
during a fast spin-up near the breakup rotation period. Such a landslide would
inevitably form a particulate disk around an asteroid with a short timescale
($\sim 3$ hours). However, the long-term full dynamical evolution is not
investigated. Here, we perform a continuous simulation ($\sim 700$ hours) that
investigates the sequence of events from the surface landslide that forms a
top-shaped asteroid and a particulate disk to disk evolution. We show that the
disk quickly spreads and produces moons (within $\sim 300$ hours). The mass of
the formed moon is consistent with what is observed around the top-shaped
asteroids. We also demonstrate that an equatorial ridge is naturally formed
because a fraction of the disk particles re-accretes selectively onto the
equatorial region of the primary. We envision that Ryugu and Bennu could once
have an ancient moon that was later lost due to a successive moon's orbital
evolution. Alternatively, at the top-shaped asteroid that has a moon, such as
Didymos, no significant orbital evolution of the moon has occurred that would
result in its loss. Our study would also be qualitatively applicable to any
rubble-pile asteroids near the breakup rotation period.
