Departament d'Astronomia i Astrofísica
Universitat de València

    Masers in Evolved Stars

Jean-François Desmurs

Observatorio Astronómico Nacional, Madrid

Seminari del departament d'Astronomia i Astrofísica

Dimecres 07 novembre 2012



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 masersobserved and how we can use them as astronomical tools to probe in-situ different physical parameters.