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.
P. Whitelock, M. Kasliwal and M. Boyer
Thu, 23 Feb 17
Comments: 5 pages, 4 figures, to appear in Proceedings of “Wide-Field Variability Surveys: A 21st Century Perspective”