Mass contained in the CZ of a 1.3 M_⊙ star as a function of its age during the PMS contraction phase (solid line). The right scale shows the iron abundance level resulting from accretion. The plot assumes the Siess et al. (2000) models for pre-main-sequence stars with solar metallicity. The rise in iron abundance caused by the ingestion of 1, 6, and 20 M_⊕ of pure iron (dashed lines, from right to left) is highly dependent on the thickness of the CZ and, consequently, on the stellar age. The dotted vertical line is located at the age estimated for #52, and the dotted horizontal line refers to the overabundance of #52 relative to Gamma Vel.