  Observations of pre-/proto-stellar cores in young star-forming regions show
them to be mass segregated, i.e. the most massive cores are centrally
concentrated, whereas pre-main sequence stars in the same star-forming regions
(and older regions) are not. We test whether this apparent contradiction can be
explained by the massive cores fragmenting into stars of much lower mass,
thereby washing out any signature of mass segregation in pre-main sequence
stars. Whilst our fragmentation model can reproduce the stellar initial mass
function, we find that the resultant distribution of pre-main sequence stars is
mass segregated to an even higher degree than that of the cores, because
massive cores still produce massive stars if the number of fragments is
reasonably low (between one and five). We therefore suggest that the reason
cores are observed to be mass segregated and stars are not is likely due to
dynamical evolution of the stars, which can move significant distances in
star-forming regions after their formation.
