Constraining Mass-Loss & Lifetimes of Low Mass, Low Metallicity AGB   Stars
  The evolution and lifetimes of thermally pulsating asymptotic giant branch (TP-AGB) stars suffer from significant uncertainties. We present a detailed framework for constraining model luminosity functions of TP-AGB stars using resolved stellar populations. We show an example of this method that compares various TP-AGB mass-loss prescriptions that differ in their treatments of mass loss before the onset of dust-driven winds (pre-dust). We find that models with more efficient pre-dust driven mass loss produce results consistent with observations, as opposed to more canonical mass-loss models. Efficient pre-dust driven mass-loss predicts for [Fe/H] < -1.2, lower mass TP-AGB stars (M < 1 Msun) must have lifetimes less than about 1.2 Myr. 
Philip Rosenfield, Paola Marigo, Leo Girardi, Julianne J. Dalcanton,   Alessandro Bressan, Marco Gullieuszik, Daniel Weisz, ...
astro-ph.SR astro-ph.GA