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

Abstract

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 30,280 109 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 . 55 0 . 05.

Supernovae Producing Unbound Binaries and Triples

“…As a luminous red giant, it is not surprising that V399 Aur is a long period variable. ET Tau is a fully analyzed eclipsing binary (EB), where Williamon et al (2016) report parameters of M1 ≃ 14.3, T1 ≃ 30300 K, L1 = 30500L⊙, and M2 = 6.3M⊙, T2 = 15000 K and L2 = 6400L⊙, respectively. This mass for the primary is much higher than found here (5.8-8.9M⊙), but the SED also clearly rules out the high temperature and luminosity of the Williamon et al (2016) model.…”

“…ET Tau is a fully analyzed eclipsing binary (EB), where Williamon et al (2016) report parameters of M1 ≃ 14.3, T1 ≃ 30300 K, L1 = 30500L⊙, and M2 = 6.3M⊙, T2 = 15000 K and L2 = 6400L⊙, respectively. This mass for the primary is much higher than found here (5.8-8.9M⊙), but the SED also clearly rules out the high temperature and luminosity of the Williamon et al (2016) model. In particular, the SED clearly breaks going into the UV rather than continuing the Rayleigh-Jeans rise that would be expected for 30000 K star.…”