Intrinsic stellar mass flux and steady stellar winds

Abstract

The conventional view that winds from stars like the Sun result from the existence of a hot corona and a low-pressure interstellar medium has recently been challeanged by R. N. Thomas and collegues. They suggest that the rates of mass loss from these and other stars are determined by conditions imposed on the flow at or below photospheric levels and that the warm chromosphere and hot corona of a solar-like star are simply consequences of this imposed photospheric flow and dissipation in the resultant stellar wind. We have examined this suggestion through the application of gas dynamic theories including dissipation. Extensive analytic and numerical calculations for both polytropic and thermally conductive flows, with viscosity included, indicate that the specification of an arbitrary intrinsic mass flux is not consistent with steady, radial, spherically symmetric flow in the absence of energy addition. We conclude that there is at present no theoretical support for the suggestion of Thomas and colleagues, and that if any such support is to be found, it will require, at the very least, a more extensive theoretical gas dynamic analysis, including explicit time dependence, spatial inhomogeneties, and/or nonclassical momentum and energy transport.