THE ECLIPSING BINARY CEPHEID OGLE-LMC-CEP-0227 IN THE LARGE MAGELLANIC CLOUD: PULSATION MODELING OF LIGHT AND RADIAL VELOCITY CURVES
- INAF-Osservatorio astronomico di Capodimonte, Via Moiariello 16, I-80131 Napoli (Italy)
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{sub Sun }-and mean effective temperature-T{sub e} = 6100 {+-} 50 K-do agree with observed estimates with an accuracy better than 1{sigma}. 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-{mu}{sub 0,LMC} = 18.50 {+-} 0.02 {+-} 0.10 (syst) mag-agree quite well with similar estimates in the recent literature.
- OSTI ID:
- 22130699
- Journal Information:
- Astrophysical Journal Letters, Vol. 768, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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