2016MNRAS.463.1269B

The mass-loss rates of red supergiants (RSGs) govern their evolution towards supernova and dictate the appearance of the resulting explosion. To study how mass-loss rates change with evolution, we measure the mass-loss rates ({dot}M) and extinctions of 19 RSGs in the young massive cluster NGC 2100 in the Large Magellanic Cloud. By targeting stars in a coeval cluster, we can study the mass-loss rate evolution whilst keeping the variables of mass and metallicity fixed. Mass-loss rates were determined by fitting DUSTY models to mid-IR photometry from WISE and Spitzer/IRAC. We find that the {dot}M in RSGs increases as the star evolves, and is well described by {dot}M prescription of de Jager, used widely in stellar evolution calculations. We find that the extinction caused by the warm dust is negligible, meaning the warm circumstellar material of the inner wind cannot explain the higher levels of extinction found in the RSGs compared to other cluster stars. We discuss the implications of this work in terms of supernova progenitors and stellar evolution theory. We argue that there is little justification for substantially increasing the {dot}M during the RSG phase, as has been suggested recently in order to explain the absence of high-mass Type IIP supernova progenitors. We also argue that an increase in reddening towards the end of the RSG phase, as observed for the two most evolved cluster stars, may provide a solution to the RSG problem.