Investigating stellar wind dynamics of WR135: A pulsating WC8-type star

We report high-frequency pulsations in WR135 from short cadence optical photometric and spectroscopic time series surveys. The harmonics up to 6ᵗʰ order are detected from the integrated photometric flux variation while the comparatively weaker 8ᵗʰ harmonic is detected from the varying strengths of the least blended emission lines. We investigate the atmospheric stratification of the stellar winds of WR135 using a radiative transfer modeling code, CMFGEN, and find the physical conditions that can support the propagation of such pulsations. From our study, we find that the sub-sonic layers of the atmosphere are close to the Eddington limit and are launched by the Fe-opacity. While the outer optically thin super-sonic winds (τᵣₒₛₛ=0.1-0.01) are driven by the He II and C IV opacities. The stratified winds above the sonic point undergo velocity perturbation that can lead to clumps. We find that the optically thin supersonic winds (τᵣₒₛₛ=0.1-0.01) contain dense smaller clumps (f=0.2-0.3) that oscillate under the higher-order harmonics of the pulsation. These clumps grow larger (f=0.1), dominate the outer stellar winds (τᵣₒₛₛ=0.01-0.001), and oscillate under the lower-order harmonics.