Orbital Solutions and Absolute Elements of the Massive Algol Binary ET Tauri

We acquired differential UBV photoelectric photometry and radial velocities of the relatively bright, understudied, massive Algol binary ET Tau and utilized the Wilson-Devinney (WD) analysis program to obtain a simultaneous solution of these observations. To improve the orbital ephemeris, the V measurements from the ASAS program were also analyzed. Because of the very rapid rotation of the significantly more massive and hotter component (B2/3 spectral class), only radial velocities of the secondary component, which has a ∼B7 spectral class, could be measured. We derive masses of ${M}_{1}=14.34\pm 0.28\,{M}_{\odot }$ and ${M}_{2}=6.339\pm 0.117\,{M}_{\odot }$ and equal-volume radii of ${R}_{1}=6.356\pm 0.056\,{R}_{\odot }$ and ${R}_{2}=11.84\pm 0.10\,{R}_{\odot }$ for the primary and secondary, respectively. The secondary is filling its Roche lobe, so the system is semi-detached. The effective temperature of the secondary was held fixed at 15,000 K, and the primary\u27s temperature was found to be $\mathrm{30,280}\pm 109$ K. The system, which has a period of 5.996883 ± 0.000002 days, is assumed to have a circular orbit and is seen at an inclination of $79\buildrel{\circ}\over{.} 55\pm 0\buildrel{\circ}\over{.} 05$