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A&A 367, 1000-1010 (2001)
DOI: 10.1051/0004-6361:20000565
Self-similar evolution of wind-blown bubbles with mass-loading by conductive evaporation
J. M. Pittard, J. E. Dyson and T. W. HartquistDepartment of Physics & Astronomy, The University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
(Received 13 November 2000 / Accepted 18 December 2000)
Abstract
We present similarity solutions for adiabatic bubbles that are blown by
winds having time dependent mechanical luminosities and that are each
mass-loaded at a rate per unit volume proportional to
,
where T is the temperature, r is the distance from the bubble center,
and 
is a constant. In the limit of little mass loading a
similarity solution found by Dyson (1973) for expansion into a
smooth ambient medium is recovered. For solutions that give the mass of
swept-up ambient gas to be less than the sums of the masses of the wind
and the evaporated material,
. The Mach number in
a shocked mass-loaded wind shows a radial dependence that varies qualitatively
from solution to solution. In some cases it is everywhere less than unity in
the frame of the clumps being evaporated, while in others it is everywhere
greater than unity. In some solutions the mass-loaded shocked wind undergoes
one or two sonic transitions in the clump frame. Maximum possible values
of the ratio of evaporated mass to stellar wind mass are found as a
consequence of the evaporation rates dependence on temperature and the
lowering of the temperature by mass-loading. Mass-loading tends
to reduce the emissivity in the interior of the
bubble relative to its limb, whilst simultaneously increasing the central
temperature relative to the limb temperature.
Key words: hydrodynamics -- shock waves -- stars: mass-loss -- ISM: bubbles -- galaxies: active
Offprint request: J. M. Pittard, jmp@ast.leeds.ac.uk
SIMBAD Objects in preparation
© ESO 2001