2013ApJ...768L...6M

We performed a new and accurate fit of light and radial velocity curves of the Large Magellanic Cloud (LMC) Cepheid–OGLE-LMC-CEP-0227–belonging to a detached double-lined eclipsing binary system. We computed several sets of nonlinear, convective models covering a broad range in stellar mass, effective temperature, and chemical composition. The comparison between theory and observations indicates that current theoretical framework accounts for luminosity–V and I band–and radial velocity variations over the entire pulsation cycle. Predicted pulsation mass–M = 4.14±0.06 M_☉–and mean effective temperature–T_e= 6100±50 K–do agree with observed estimates with an accuracy better than 1σ. The same outcome applies, on average, to the luminosity amplitudes and to the mean radius. We find that the best-fit solution requires a chemical composition that is more metal-poor than typical LMC Cepheids (Z = 0.004 versus 0.008) and slightly helium enhanced (Y = 0.27 versus 0.25), but the sensitivity to He abundance is quite limited. Finally, the best-fit model reddening–E(V - I) = 0.171±0.015 mag–and the true distance modulus corrected for the barycenter of the LMC–µ_0, LMC_= 18.50±0.02 ±0.10 (syst) mag–agree quite well with similar estimates in the recent literature.