Evolution of the First Stars: CNO yields and the C-rich extremely metal poor stars

Rotating massive stars at Z=10^-8 and 10^-5 lose a great part of their initial mass through stellar winds. The chemical composition of the rotationally enhanced winds of very low Z stars is very peculiar. The winds show large CNO enhancements by factors of 10³ to 10⁷, together with large excesses of ¹³C and ¹⁷O and moderate amounts of Na and Al. The excesses of primary N are particularly striking. When these ejecta from the rotationally enhanced winds are diluted with the supernova ejecta from the corresponding CO cores, we find [C/Fe], [N/Fe],[O/Fe] abundance ratios very similar to those observed in the C-rich extremely metal poor stars (CEMP). We show that rotating AGB stars and rotating massive stars have about the same effects on the CNO enhancements. Abundances of s-process elements and the ¹²C/¹³C ratio could help us to distinguish between contributions from AGB and massive stars. On the whole, we emphasize the dominant effects of rotation for the chemical yields of extremely metal poor stars.