NOW! [SEMINARI] Masers in Evolved Stars, Jean- Fran çois Desmurs

[Eduardo Ros]

On Nov 7, 2012, at 12:26 PM, Enric Marco wrote:

> Title:  Masers in Evolved Stars
>
> By:  Jean-François Desmurs
>
> From:   Observatorio Astronómico Nacional, Madrid.
>
> Where: Seminari del departament d'Astronomia i Astrofísica
>
> Date: Dimecres 07 novembre 2012
>
> Hour: 15:00
>
> Abstract
>
> Asymptotic Giant Branch (AGB) stars are the final evolution stage of
> low and intermediate mass stars. During this phase, they lose a lot of
> matter in the form of stellar winds. As the atmosphere of these stars
> is enriched by convection from the elements synthesized in their core,
> this mass loss enriches the interstellar medium of the Galaxy in heavy
> elements, oxygen, carbon, dust...  Astrophysical masers are
> characterized by showing very large brightness equivalent
> temperatures. This property of the maser emission has been extensively
> used to probe the inner shells of the thick circumstellar envelopes
> that surrounds AGB and post-AGB sources. They provide excellent
> tracers of the dynamic of the envelope at different distances from the
> central stars.  These regions are of particular interest, since it is
> where the processes of dust formation and gas acceleration
> (responsible for the mass loss of the star and the formation of the
> envelope) occur.  I will discuss the different circumstellar masers
> observed and how we can use them as astronomical tools to probe
> in-situ different physical parameters.
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