ALMA discovery of a rotating SO/SO${}_2$ flow in HH212. A possible MHD disk wind?

Abstract

We wish to constrain the possible contribution of a magnetohydrodynamic disk wind (DW) to the HH212 molecular jet. We mapped the flow base with ALMA Cycle 4 at 0.13"$\sim$ 60 au resolution and compared these observations with synthetic DW predictions. We identified, in SO/SO${}_2$, a rotating flow that is wider and slower than the axial SiO jet. The broad outflow cavity seen in C${}^{34}$S is not carved by a fast wide-angle wind but by this slower agent. Rotation signatures may be fitted by a DW of a moderate lever arm launched out to $\sim$ 40 au with SiO tracing dust-free streamlines from 0.05-0.3 au. Such a DW could limit the core-to-star efficiency to $\le$50%.

Accepted for publication in A&A letters, final language edited version