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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20161020T103000
DTEND;TZID=Atlantic/Canary:20161020T113000
UID:iactalks-951
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/951
CREATED:2016-10-20T10:30:00+01:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:Metallicity distribution of Galactic thin disk & halo using Cepheid
 s & RR Lyrae
DESCRIPTION:Metallicity distribution of Galactic thin disk & halo using Cep
 heids & RR Lyrae\nProf. Giuseppe Bono\n\nWe present new results concerning
  the radial gradients (Fe, alpha, s- and r-process elements) across the Ga
 lactic thin disk. We use young (t<300 Myr, classical Cepheids) stellar 
 tracers for  which we collected high resolution spectra with UVES at 
 VLT together with similar estimates avaialble in the literature. The inves
 tigated elements display well defined negative gradients when moving from 
 the innermost to the outermost regions. Moreover, we also found that the r
 adial gradients of the neutron capture elements are positive as a function
  of age (pulsation period). Thus suggesting an age dependence similar to a
 lpha-elements. On the other hand, the slopes of [elements/Fe] vs Galactoce
 ntric distance are more positive than for alpha-elements. We discuss plaus
 ible working hypotheses to take account of the difference, and perform a d
 etailed comparison with similar abundances for dwarf and giant stars avail
 able in the literature. We also discuss the abundance ratio between s- and
  r-process elements (La/Eu) and between heavy and light s-process elements
  (La/Y)  and outline their impact on the chemical enrichment history 
 of the Galactic thin disk. Finally, we present new results concerning the 
 iron gradient of the Galactic halo using old (t>10 Gyr, RR Lyrae) stell
 ar tracers for which we collected high-resolution spectra  with UVES 
 at VLT together with metallicity estimates based on low-resolution spectra
  available in the literature. We discuss the difference with the metallici
 ty gradient and spread in metallicity of the M31 halo and the impact on th
 eir early formation and evolution.
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