Speaker
Jonathan Mackey
(AIfA, Uni Bonn, and I. Physikalisches Institut, Uni. Köln)
Description
Mass loss from massive stars is very important for determining their evolution and death, but their wind properties can be difficult to measure and are often very uncertain. Main sequence massive stars have fast and highly ionized winds, driving bubbles in their surroundings that have proven surprisingly difficult to detect. We have run simulations showing that wind bubbles are typically very asymmetric and do not fill their HII regions. X-ray emission from the shocked wind is very weak, about 0.1% of the input energy, with the rest being dissipated by mixing with cooler photoionized gas. It appears likely that arcs of infrared emission (often seen within HII regions) can be explained as the outer edges of asymmetric wind bubbles, and this can potentially be used to constrain stellar wind strength.