14/11/2012 – 14h00 – Auditório IAG – IAG/USP
Título/Title: Spectroscopy from R=300 to 30000: metal-poor stars and the chemical evolution of the GalaxyResumo/Abstract:
Long-lived low-mass stars have the ability to preserve in their atmosphere, for the most part of their lives, wealthy information about the medium from which they were formed. This information is mostly unchanged over timescales of billions of years, allowing astronomers to have a clear view of what happened at the time of their formation. In this context, metal-poor stars act as a probe for Galactic chemical and dynamical evolution. In this talk I will show how different spectral resolutions can give different perspectives on the problematic associated with metal-poor stars in the Galaxy, and how these apparently distinct types of studies work together. While low-resolution studies rely on statistics, and can trace the general behavior of a given population, high-resolution spectroscopy works on an individual basis, and can provide complete chemical abundance patterns of the observed targets. In particular, I will present results of a high-resolution spectroscopic study of two newly discovered carbon-enhanced metal-poor stars. The comparison between observations and theoretical models will help address questions such as the onset of the s-process in the Galaxy and its operation at low-metallicity, as well as provide clues on the chemical imprint left by the first generations of stars in the early Universe.