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JOINT ICTP-OATS-SISSA-UNI/TS COLLOQUIUM
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Speaker: Martin Asplund (MPA, Garching, D)

Title: Does the Sun have a subsolar metallicity?
Date: Thursday, May 20th, 2010
Time: 15:00
Venue: Villa Bazzoni

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Abstract: The solar chemical composition is an important ingredient in our understanding of the formation, structure and evolution of both the Sun and our solar system. Furthermore, it is an essential reference standard against which the elemental contents of other astronomical objects are compared. In recent years the solar abundances of the most common metals -- C, N, O and Ne -- have undergone a quite dramatic downward revision, driven by our work on developing realistic 3D hydrodynamical solar model atmospheres, non-LTE line formation and improved atomic/molecular data. While welcomed by most areas of astronomy, these changes have caused a great deal of consternation for helioseismology. I will present our recently completed work on redetermining the solar abundances of all elements, which appeared in ARAA last year. I will also discuss how the Sun compares with other solar-type stars. Surprisingly the Sun is unusual in its chemical properties, a fact that most likely is due to it hosting planets and quite possibly terrestrial planets. Our findings open the enthralling prospect of being able to identify stars harbouring planets purely from their chemical compositions.
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contact: Gabriele Cescutti (UNI/TS)