The most massive stars provide an essential source of recycled material for
young clusters and galaxies. While very massive stars (VMS, M>100M) are
relatively rare compared to O stars, they lose disproportionately large amounts
of mass already from the onset of core H-burning. VMS have optically thick
winds with elevated mass-loss rates in comparison to optically thin standard
O-star winds. We compute wind yields and ejected masses on the main sequence,
and we compare enhanced mass-loss rates to standard ones. We calculate solar
metallicity wind yields from MESA stellar evolution models in the range 50 -
500M, including a large nuclear network of 92 isotopes, investigating not only
the CNO-cycle, but also the Ne-Na and Mg-Al cycles. VMS with enhanced winds
eject 5-10 times more H-processed elements (N, Ne, Na, Al) on the main sequence
in comparison to standard winds, with possible consequences for observed
anti-correlations, such as C-N and Na-O, in globular clusters. We find that for
VMS 95% of the total wind yields is produced on the main sequence, while only
~5% is supplied by the post-main sequence. This implies that VMS with enhanced
winds are the primary source of 26Al, contrasting previous works where
classical Wolf-Rayet winds had been suggested to be responsible for Galactic
26Al enrichment. Finally, 200M stars eject 100 times more of each heavy element
in their winds than 50M stars, and even when weighted by an IMF their wind
contribution is still an order of magnitude higher than that of 50M stars.Comment: Accepted for publication in MNRAS. 14 pages, 10 figure