2008ApJ...682..492W

We present results from an optical spectroscopic investigation of the massive binary system [L72] LH 54-425 in the LH 54 OB association in the Large Magellanic Cloud. We revise the ephemeris of [L72] LH 54-425 and find an orbital period of 2.24741±0.00004 days. We find spectral types of O3 V for the primary and O5 V for the secondary. We made a combined solution of the radial velocities and previously published V-band photometry to determine the inclination for two system configurations, i=52⁺²_–3degrees for the configuration of the secondary star being more tidally distorted and i=55°±1° for the primary as the more tidally distorted star. We argue that the latter case is more probable, and this solution yields masses and radii of M₁=47±2 M_☉ and R₁=11.4±0.1 R_☉for the primary, and M₂=28±1 M_☉ and R₂=8.1±0.1 R_☉for the secondary. Our analysis places LH 54-425 among the most massive stars known. Based on the position of the two stars plotted on a theoretical HR diagram, we find the age of the system to be ∼1.5 Myr.