  According to the core accretion theory, circumbinary embryos can form only
beyond a critical semimajor axis (CSMA). However, due to the relatively high
density of solid materials in the inner disk, significant amount of small
planetesimals must exist in the inner zone when embryos were forming outside
this CSMA. So embryos migration induced by the planetesimal swarm is possible
after the gas disk depletion. Through numerical simulations, we found (i) the
scattering-driven inward migration of embryos is robust, planets can form in
the habitable zone if we adopt a mass distribution of MMSN-like disk; (ii) the
total mass of the planetesimals in the inner region and continuous
embryo-embryo scattering are two key factors that cause significant embryo
migrations; (iii) the scattering-driven migration of embryos is a natural
water-deliver mechanism. We propose that planet detections should focus on the
close binary with its habitable zone near CSMA.
