  We develop a semi-analytic model for planet formation during the pre-main
sequence contraction phase of a low mass star. During this evolution, the
stellar magnetosphere maintains a fixed ratio between the inner disk radius and
the stellar radius. As the star contracts at constant effective temperature,
the `snow line', which separates regions of rocky planet formation from regions
of icy planet formation, moves inward. This process enables rapid formation of
icy protoplanets that collide and merge into super-Earths before the star
reaches the main sequence. The masses and orbits of these super-Earths are
consistent with super-Earths detected in recent microlensing experiments.
