Dust cleansing of star-forming gas I: Did radiation from bright stars
  affect the chemical composition of the Sun and of M67?
  The possibility that the solar chemical composition, as well as the similar
composition of the rich open cluster M67, have been affected by dust cleansing
of the pre-solar/pre-cluster cloud, due to the radiative forces from bright
early-type stars in its neighbourhood, is explored. Estimates, using
semi-analytical methods and essentially based on momentum conservation, are
made of possible dust-cleansing effects. Our calculations indicate that the
amounts of cleansed neutral gas are limited to a relatively thin shell
surrounding the HII region around the early-type stars. It seems possible that
the proposed mechanism acting in individual giant molecular clouds may produce
significant abundance effects for masses corresponding to single stars or small
groups of stars. The effects of cleansing are, however, severely constrained by
the thinness of the cleansed shell of gas and by turbulence in the cloud, why
the mechanism can hardly be important in cleansing masses corresponding to rich
clusters, such as the mass of the original M67.
