2017AcA....67..329S

This paper presents a detailed analysis of the light and radial velocity curves of the semi-detached eclipsing binary system OGLE-LMC-ECL-09937. The system is composed of a hot, massive and luminous primary star of a late-O spectral type, and a more evolved, but less massive and luminous secondary, implying an Algol-type system that underwent a mass transfer episode. We derive masses of 21.04±0.34 M_☉ and 7.61±0.09 M_☉ and radii of 9.93±0.06 R_☉ and 9.18±0.04 R_☉, for the primary and the secondary component, respectively, which make it the most massive known Algol-type system with masses and radii of the components measured with