  Dynamical considerations, presented herein via analytic scalings and
numerical experiments, imply that Earth-mass planets accreting in regions that
become habitable zones of M dwarf stars form within several million years.
Temperatures in these regions during planetary accretion are higher than those
encountered by the material that formed the Earth. Collision velocities during
and after the prime accretionary epoch are larger than for Earth. These factors
suggest that planets orbiting low mass main sequence stars are likely to be
either too distant (and thus too cold) for carbon/water based life on their
surfaces or have abundances of the required volatiles that are substantially
less than on Earth.
