Author(s): A. Tielens, C. Pabst, Leiden Observatory, Leiden University, Leiden, NETHERLANDS|
Institution(s): 1. Leiden Observatory, Leiden University, Leiden, Netherlands.
Contributing team(s): C+Squad
Mechanical and radiative energy input by massive stars stir up the environment, heat the gas, produce cloud & intercloud phases in the interstellar medium and disrupt molecular clouds, the birthsites of new stars. Ionization by UV photons, stellar wind action and supernova explosions control molecular clouds lifetimes. Theoretical studies predict that momentum injection by radiation dominates by far over momentum injected by a stellar wind, but this has hitherto been difficult to assess observationally. Velocity-resolved large-scale images in the fine structure line of ionized carbon ([CII]) provide an observational diagnostic of the radiative energetics and the dynamics of the ISM in the immediate vicinity of massive stars. Here, we present the [CII] 1.9 THz (158 μm) study of ~1 square degree region (~7pc in diameter) at a resolution of 16" (0.03pc) of the nearest region of massive star formation, Orion. The results reveal that the stellar wind originating from the star, θ1Ori C, has created a ~2pc sized bubble by sweeping up a 2600 Msun shell expanding at 13 km/s. This shows that the stellar wind mechanical energy is coupled very efficiently to the molecular core and its action dominates over photo-ionization/evaporation or future supernova explosions.