Testing Mass Loss in Large Magellanic Cloud Cepheids using Infrared and Optical Observations II. Predictions and Tests of the OGLE-III Fundamental-Mode Cepheids

摘要

In this article, we test the hypothesis that Cepheids have infrared excessesdue to mass loss. We fit a model using the mass-loss rate and the stellarradius as free parameters to optical observations from the OGLE-III survey andinfrared observations from the 2MASS and SAGE data sets. The sample of Cepheidshave predicted minimum mass-loss rates ranging from zero to $10^{-8}M_\odot$$yr^{-1}$, where the rates depend on the chosen dust properties. We use thepredicted radii to compute the Period-Radius relation for LMC Cepheids, and toestimate the uncertainty caused by the presence of infrared excess fordetermining angular diameters with the infrared surface brightness technique.Finally, we calculate the linear and non-linear Period-Luminosity (P-L)relations for the LMC Cepheids at VIJHK + IRAC wavelengths and we find that theP-L relations are consistent with being non-linear at infrared wavelengths,contrary to previous results.