Transit Flow Models for Low‐ and High‐Mass Protostars

In this work, the gas infall and the formation of outflows around low andhigh mass protostars are investigated. A radial self-similar approach to modelthe transit of the molecular gas around the central object is employed. Weinclude gravitational and radiative fields to produce heated pressure-drivenoutflows with magneto-centrifugal acceleration and collimation. Outflowsolutions with negligible or vanishing magnetic field are reported. Theyindicate that thermodynamics is a sufficient engine to generate an outflow. Themagnetized solutions show dynamically significant differences in the axialregion, precisely where the radial velocity and collimation are the largest.They compare quantitatively well with observations. The influence of theopacity on the transit solutions is also studied. It is found that, when dustis not the dominant coolant, such as in the primordial universe, mass infallrates have substantial larger values in the equatorial region. This suggeststhat star forming in a dust-free environment should be able to accrete muchmore mass and become more massive than present day protostars.It is alsosuggested that molecular outflows may be dominated by the global transit ofmaterial around the protostar during the very early stages of star formation,especially in the case of massive or dust-free star formation.Comment: 19 pages, 15 figures, accepted by Ap