Precise physical parameters of three late-type eclipsing binary giant stars in the Large Magellanic Cloud

Le résumé fourni par la source

Context. Detached eclipsing binaries (DEBs) allow for the possibility of a precise characterization of their stellar components. They offer a unique opportunity for deriving their physical parameters nearly independent of a model for a number of systems consisting of late-type giant stars. We aim to expand the sample of low-metallicity late-type giant stars with precisely determined parameters. Aims. We determine the fundamental parameters, such as the mass and radius, or the effective temperature for three long-period late-type eclipsing binaries from the Large Magellanic Cloud: OGLE-LMC-ECL-25304, OGLE-LMC-ECL-28283, and OGLE-IV LMC554.19.81. Subsequently, we determine the evolutionary stages of the systems. Methods. We fit the light curves from the OGLE project and radial velocity curves from high-resolution spectrographs using the Wilson-Devinney code. The spectral analysis was performed with the GSSP code and resulted in the determination of atmospheric parameters such as effective temperatures and metallicities. We used the isochrones provided by the MIST models based on the MESA code to derive the evolutionary status of the stars. Results. We present the first analysis of three DEBs composed of similar helium-burning late-type stars that pass through the blue loop. The estimated masses for OGLE-LMC-ECL-29293 (G4III + G4III) are M1 = 2.898 ± 0.031 and M2 = 3.153 ± 0.038 M⊙, and the stellar radii are R1 = 19.43 ± 0.31 and R2 = 19.30 ± 0.31 R⊙. OGLE-LMC-ECL-25304 (G4III + G5III) has stellar masses of M1 = 3.267 ± 0.028 and M2 = 3.229 ± 0.029 M⊙ and radii of R1 = 23.62 ± 0.42 and R2 = 25.10 ± 0.43 R⊙. OGLE-IV LMC554.19.81 (G2III + G2III) has masses of M1 = 3.165 ± 0.020 and M2 = 3.184 ± 0.020 M⊙ and radii of R1 = 18.86 ± 0.26 and R2 = 19.64 ± 0.26 R⊙. All masses were determined with a precision better than 2% and the precision for the radii is better than 1.5%. The ages of the stars are in the range of 270–341 Myr.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.