populations, but during the last two decades they have been shown to harbour multiple stellar populations. Observations imply that a considerable fraction (up to 70%) of the stars currently in GCs has a very different chemical composition from the initial population [see e.g. @gratton12]. They indicate that a second (and in some cases even higher order, e.g. @piotto07) population[^1] of stars has formed from material enriched by ejecta from first generation stars.

To explain the formation of these enriched stellar populations, several scenarios have been proposed [see e.g. @decressin07-1; @dercole08; @de_mink09; @bastian13-2]. One of the recently proposed scenarios applies in particular to star formation in GCs, but could, in theory, also leave its signature on stellar systems that are less dense. @bastian13-2, hereafter B13, have suggested a scenario in which the enriched population is not formed by a second star formation event, but rather by the accretion of enriched material, that was expelled by the high-mass stars of the initial population, onto the low-mass stars of the same (initial) population. Because Bondi-Hoyle accretion, i.e. gravitational focusing of material onto the star, is unlikely to be efficient in a GC environment with a high velocity dispersion, they suggest that the protoplanetary 