Modeling Mass-Loss and Infrared Excess in Large Magellanic Cloud Cepheids

The purpose of this preliminary work is to determine if Large Magellanic Cloud (LMC) Cepheids have stellar winds. If a Cepheid undergoes mass loss then at some distance from the star, a fraction of the gas becomes dust, which causes an infrared excess. Mass loss is tested using OGLE II optical observations and SAGE infrared observations for a sample of 488 Cepheids. The resultant mass-loss rates range from $10^{-12}$ to $10^{-7}$ $M_\odot/yr$. Using the mass--loss model we compute infrared stellar luminosities for the sample of Cepheids and compare predicted infrared PL relations with observed relations. The predicted relations not only vary from the observed relations, implying mass loss plays a significant role, but also show evidence for non-linearity. It is determined that mass loss is important for LMC Cepheids.
Comment: 4 pages, 3 figures, 1 table. To appear in the proceedings of IAU Symposium 256, The Magellanic System: Stars, Gas, and Galaxies, Ed J. Th. van Loon, J. M. Oliveira, CUP