2009AJ....137.3222W

I present results from an optical spectroscopic investigation of the binary system HD 42401 (V1388 Ori; B2.5 IV-V + B3 V). A combined analysis of V-band photometry and radial velocities indicates that the system has an orbital period of 2.18706±0.00005 days and an inclination of 75°.5 ±0°.2. This solution yields masses and radii of M₁= 7.42±0.08 M_☉ and R₁= 5.60±0.04 R_☉for the primary and M₂= 5.16 ±0.03 M_☉ and R₂= 3.76±0.03 R_☉for the secondary. Based on the position of the two stars plotted on a theoretical Hertzsprung-Russell diagram, I find that the age of the system is ≳ 25 Myr and that both stars appear overluminous for their masses compared to single-star evolutionary tracks. A fit of the spectral energy distribution based on photometry from the literature yields a distance of 832±89 pc to HD 42401.