Gas Dynamics Driven by an O-type YSO: from the Parsec Scale down to 100 AU

Alberto Sanna, MPIfR Bonn - 18.06.18

Abstract:

In order to understand how the most massive stars form, and how they influence the surrounding Interstellar Medium, we need to study the kinematics and physical properties of gas associated with the star formation process at different scales. Making use of the most sensitive (interferometric) facilities available to date, we have conducted a multi-frequency observational campaign, at increasing angular resolution, targeting a massive Young Stellar Object (YSO) in the Star-Forming Region G023.01-00.41. I will review the morphological properties and energetics of the gas flow powered by this massive (O-type) YSO at all the relevant scales of emission. In particular, I will present the first direct imaging of an accretion disk revealed with ALMA around an O-type YSO (Sanna, Koelligan et al. 2018). The disk appears warped, and, by comparing the observed and modeled (including full radiation transfer) pv-plots along the disk plane, I will show there is a significant infalling motion towards the central star. The circumstellar disk drives a molecular jet which arises from the inner regions, where rotation takes over and approaches centrifugal equilibrium. I will finally present new ALMA dust polarization observations which unveil the magnetic field morphology across the warped disk.