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Spectroscopic observations of stellar granulation

Iván Ramírez
Max Planck Institute for Astrophysics

Despite the remarkable progress made by theorists, convection in stellar atmospheres remains poorly understood. This is, in part, due to the lack or incompleteness of observational data against which the proposed models may be tested. Fortunately, the effects of surface convection (granulation) can be detected and quantified in very high quality spectra. We are acquiring this type of data for a number of stars covering most of the HR diagram to test the predictions of models of stellar surface convection. Spectral line bisectors and core wavelength shifts are being both measured and modeled, allowing us to validate and/or reveal the limitations of state-of-the-art 3D hydrodynamic model atmospheres of different stellar parameters. I will show the status of this project and preliminary results. I will also discuss the importance of validating 3D model atmospheres in the context of stellar parameter and elemental abundance determinations.

2010 March 25, 13:30

Centro de Astrofísica da Universidade do Porto (Auditorium)
Rua das Estrelas, 4150-762 Porto

Instituto de Astrofísica e Ciências do Espaço Universidade do Porto Faculdade de Ciências da Universidade de Lisboa Fundação para a Ciência e a Tecnologia
Outreach at IA