S20B0112abst
S20B0112
Mass loss from stars in the last stages of life – including AGB and some RSG stars – governs their ultimate destiny as a supernovae or PNe, and is crucial for galactic chemical enrichment. But the mechanisms driving the mass loss for these AGB stars remain poorly understood; to accelerate a dust-driven wind requires grains to form too close to the star, while aspheric and clumpy envelopes require some additional mechanism. Moreover, stellar pulsations also play a key role. In a notable example, the RSG star Betelgeuse has recently undergone a mysterious dimming event, possibly linked to its pulsating behaviour, or alternatively due to a dusty ‘cloud’ in its atmosphere. Here we propose to use a unique set of instrumentation to directly image a) the dusty mass-loss features surrounding these stars and b) the pulsation-induced shocks formed in the outer atmospheres via their Hα emission. SCExAO+VAMPIRES is one of the only instruments in the world that can achieve the extreme levels of resolution needed to image stellar surface features and mass-loss, and in both polarised light and Hα SDI. By directly examining the mass-loss process at its source (the inner circumstellar environment), these powerful observations will yield critical insight into the mystery of the mass-loss process.
This document was translated from LATEX by HEVEA.