S19A0099

Mass loss from stars in the last stages of life 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. Here we propose to use a unique set of instrumentation to directly image a) the pulsation-induced shocks formed in the outer atmospheres via their Hα emission, b) the dusty mass-loss shell directly surrounding (as close as 1.5 R) the star and c) the extended mass-loss nebula. These observations will be made possible by exploiting SCExAO’s unique set of capabilities: milliarcsecond-scale super-diffraction-limited imaging in differential polarisation and emission line wavelengths using VAMPIRES, and high-contrast, spectrally resolved arcsecond-scale imaging using CHARIS. 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 proposal is a re-submission of our successful 2017A proposal, which was lost to weather.


This document was translated from LATEX by HEVEA.