Thermodynamical and dynamical evolution of a self-gravitating object and the influence of ionization |
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| Authors: | A Di Fazio F Palla |
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| Institution: | (1) Osservatorio Astronomico di Roma and Istituto di Astrofisica Spaziale, Frascati, Italia;(2) Osservatorio Astrofisico di Arcetri, Firenze and Istituto di Astrofisica Spaziale, Frascati, Italia |
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| Abstract: | We use a simple equation of state, in which the adiabatic index depends on opacity and ionization and we integrate the dynamical and thermodynamical equations for the gravitational collapse of a typical solar composition protocloud, up to the virialization of the energies. Following the evolution of the thermal energy and ionization fraction, violent bounces are obtained at the sudden hardening of the equation of state, when the material becomes ionized.We also suggest a mechanism to explain the onset of protostellar winds.We introduce radiation losses in the model, and integrate again the modified equations, studying the evolution of a 1.1M
 protocloud. The object's effective temperature stays in a confined small zone of the IR region throughout its fast ( 40 yr) evolution and its luminosity oscillates and decreases from 5000L
to 500L
. The radius starts from 35 AU and shrinks down to 140R
, before a physical instability gives birth to a strong shock wave with consequent mass loss. |
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