The Pulsation of Extremely Metal Poor AGB Stars

Two essential ingredients for high mass loss rates from AGB stars are grain formation and large amplitude pulsation. In this study, the second ingredient for high mass loss rates, stellar pulsational instability on the AGB is examined. It is found that low mass EMP AGB stars can pulsate with amplitudes similar to their more metalrich counterparts, although they need higher luminosities, so that high mass loss rates can occur from these stars. However, intermediate mass EMP AGB stars have substantially lower pulsation amplitudes and radii than their more metal-rich counterparts for all possible luminosities. It is likely that these stars will become supernovae rather than ejecting their envelopes and leaving a white dwarf remnant.