On the bipolarity of Wolf–Rayet nebulae

Wolf-Rayet stars are amongst the rarest but also most intriguing massive stars. Their extreme stellar winds induce famous multi-wavelength circumstellar gas nebulae of various morphologies, spanning from circles and rings to bipolar shapes. This study is devoted investigation formation young, asymmetric we present a 2.5-dimensional magneto-hydrodynamical toy model for simulation generated by wind-wind interaction. Our method accounts wind asymmetries, rotation, magnetisation, evolution mixing materials. It found that morphology blue supergiant ancestors tightly related geometry phase transition time interval, generating either broadened peanut-like or collimated jet-like nebula. Radiative transfer calculations our dust infrared emission at 24 $\mu$m show projected diffuse can appear as oblate, bipolar, ellipsoidal ring structures. Important projection effects work in shaping observed nebulae. might call revision classifications shells, which mostly based on their shape. Particularly, models question possibility producing pre-Wolf-Rayet responsible like NGC 6888, within single red channel scenario. We propose only be formed scenario multiple/merged systems, high-mass undergoing additional, e.g. supergiant, evolutionary stages prior phase.