Long-Period Variables in the Large Magellanic Cloud

Abstract

We present the first results from a new set of linear, radial, non-adiabatic pulsation models of long-period variables (LPVs), widely covering the space of stellar parameters corresponding to evolution along the Asymptotic Giant Branch (AGB). This coverage includes several values of metallicity and carbon-enhanced compositions consistent with the occurrence of repeated third dredge-up events. Updated atomic and molecular opacity data were included consistently with chemical composition in order to produce realistic pulsation properties of both O-rich and C-rich variables. We combined the pulsation models with a stellar population synthesis tool in order to study the population of LPVs in the Large Magellanic Cloud (LMC). We found the models to be reasonably good at reproducing the observed period–luminosity (PL) sequences, as well as the distribution of observed amplitudes. We provide a new interpretation of the PL sequences of LPVs that can bring into alignment previously discordant interpretations.