An X-ray study of mass-loss rate and wind acceleration of massive stars

By monitoring WC7 and the O5.5 binary WR 140 with the Suzaku telescope, we demonstrate a new method to measure the mass loss rates of both stars. By using the absorption column density, we found a mass-loss rate for the WC7 component: Ṁ_WC7 ~ 1.2 × 10^-5 M_⊙ yr^-1. We also measured the mass-loss rate of the companion O component using a luminosity variation in phases: Ṁ_O5.5 ~ 5 × 10^-7 M_⊙ yr^-1.