MHD Modeling of a Disk-Wind from a High-Mass Protobinary: the case of Orion Source I

TL;DR

This paper uses magnetohydrodynamic simulations to model the disk-wind from a high-mass protostar in Orion Source I, explaining observed properties and dynamics within 100 AU.

Contribution

It presents the first detailed MHD simulation of the disk-wind in Orion Source I, matching observed outflow characteristics and magnetic field properties.

Findings

MHD disk-wind model reproduces observed bipolar outflow morphology.

Simulations match observed velocity and rotational profiles.

Model supports magnetic fields as key in outflow collimation.

Abstract

Very long baseline interferometry (VLBI) observations of SiO masers in Orion Source I has enabled for the first time to resolve the outflow from a high-mass protostar in the launch and collimation region. Therefore, Source I provides a unique laboratory to study mass-loss and mass-accretion in a high-mass protostar. We numerically simulate the dynamics of the disk-wind inside 100 AU from Source I. This enables us to investigate the balance of different forces (gravitational, magnetic, thermal) regulating gas dynamics in massive star formation. In this work, we adopt magnetohydrodynamic (MHD) disk-wind models to explain the observed properties of the disk-wind from Orion Source I. The central source is assumed to be a binary composed of two 10\,$\msun$ stars in a circular orbit with an orbital separation of 7 AU. High resolution ideal MHD wind launching simulations (which prescribe disk as a boundary) are performed using the PLUTO code. The simulations are allowed to run until a steady state is obtained. MHD driven disk-wind provides a consistent model for the wide-angle flow from Source I probed by SiO masers, reproducing the bipolar morphology, the velocity amplitude and rotational profile, the physical conditions, and the magnetic field strength.