"Dusty Plasmas: stellar winds and the interstellar medium" / "Plasmas empoeirados: ventos estelares e o meio interestelar"

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

In this work, we firstly discuss the propagation of Alfvén waves in dusty plasmas found in several astrophysical environments. The wave dispersion relation is modified giving rise to new damping mechanisms. There are in the literature observational data indicating the presence of dust near the surface of cool giant and supergiant stars. We developed a stellar mass loss model where we show that a flux of Alfvén waves, damped by the dust presence,can generate a low velocity and high mass loss rate wind, in agreement with the observations. In the case of hot stars we show how it is possible to obtain the special conditions for dust growth in a wind collision model of massive binary systems. For this model it is possible to explain both, the high X-rays emissions and dust growth at the post-shock phase. Applying the idea to the $eta$ Carinae binary system, the model allows the determination of the system orbital and the stellar wind parameters. The stellar wind´s dust is then ejected to the interstellar medium. In a semi-empirical calculation we showed the importance of each stellar mass, at each evolutionary phase, on the dust feedback of the ISM. For star formation regions, we investigate the role of Alfvén waves, damped by the dust presence, on the stability of the molecular clouds. In spite of the works found in the literature, we showed that a dwarf molecular cloud, magnetically supported only, is unstable.

ASSUNTO(S)

estrelas ondas alfvén stars winds plasma poeira ventos meio interestelar interstellar medium dust alfvén waves plasma

ACESSO AO ARTIGO

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