Title: Spitzer Observations of Large Amplitude Variables in the LMC and IC 1613,
Abstract: The 3.6 and 4.5 micron characteristics of AGB variables in the LMC and IC1613
are discussed. For C-rich Mira variables there is a very clear
period-luminosity-colour relation, where the [3.6]-[4.5] colour is associated
with the amount of circumstellar material and correlated with the pulsation
amplitude. The [4.5] period-luminosity relation for dusty stars is
approximately one mag brighter than for their naked counterparts with
comparable periods.