Sonia Duffau – Sulphur and Zinc in our Galaxy as seen by the Gaia-ESO survey


“Sulphur and Zinc in our Galaxy as seen by the Gaia-ESO survey”

Sonia Daffau

Universidad Andres Bello

Sulphur (S) and Zinc (Zn) are rarely targeted by stellar abundance studies: they are difficult to measure (S in particular) and are considered to trace other alpha elements (for S) and iron (for Zn) in their abundance evolution. However, they bear great importance in Interstellar Medium studies because they are very volatile, and remain in the gas phase (where they can be measured) rather than forming dust. For all these reasons, they are the proxies of for alpha elements and iron in studying the abundances of Damped-Lyman-Alpha systems: it is thus important to investigate whether they do in fact behave as expected in local stars, where Fe and other alpha elements can be handily measured. The Gaia-ESO (GES) internal data release 4 allows us to measure S abundances in ~1300 stars, and Zn in ~1700, comprising local thin/thick disk dwarfs, and giants mostly in globular and open clusters over a variety of galactocentric radii. Sulphur appears indeed to behave as an alpha element (albeit with surprising results in 47 Tucanae), but Zn has a complex behavior, following Fe only partly, with signs of a more complex nucleosynthetic history than previously thought.

Auditorium of Physics Faculty

Thu 25 May 2017