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 \pm 0.00005 days and an inclination of 75.5 \pm 0.2 degrees .
This solution yields masses and radii of M _ { 1 } = 7.42 \pm 0.08 M _ { \odot } and R _ { 1 } = 5.60 \pm 0.04 R _ { \odot } for the primary and M _ { 2 } = 5.16 \pm 0.03 M _ { \odot } and R _ { 2 } = 3.76 \pm 0.03 R _ { \odot } for the secondary .
Based on the position of the two stars plotted on a theoretical H-R diagram , I find that the age of the system is \gtrsim 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 to HD 42401 of 832 \pm 89 parsecs .