RSAA Colloquia / Seminars / Feast-of-Facts: Thursday, 02 April 2015, 11:00-12:00; Duffield Lecture Theatre

Jeremy Goodman

"Very Massive Stars"

The upper limit to stellar masses is unclear, as is the relative importance of ’nature’ (stellar physics) and ’nurture’ (formation environment) to the limit. I will show that quasar disks may form stars with masses much larger than in giant molecular clouds. This encourages a re-examination of the limits imposed by stellar physics. We have studied pulsational instabilities of modern solar-metallicity models up to 938 solar masses. Despite some uncertainties in the linear growth rate, we conclude that these modes saturate nonlinearly at small and harmless amplitudes. Vigorous, optically thick winds driven by the Rosseland-mean opacity near 100,000 K are more likely to limit the main-sequence lifetime.