1 / 12

Study of the s-process in low mass stars of Galactic disc metallicity

Study of the s-process in low mass stars of Galactic disc metallicity. Laura Husti Roberto Gallino Sara Bisterzo. Outline: Origin of the heavy elements. Stellar Nucleosynthesis and Evolution. S-process nucleosynthesis in AGB stars at solar metallicity.

denali
Download Presentation

Study of the s-process in low mass stars of Galactic disc metallicity

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Study of the s-process in low mass stars of Galactic disc metallicity Laura Husti Roberto Gallino Sara Bisterzo

  2. Outline: • Origin of the heavy elements. • Stellar Nucleosynthesis and Evolution. • S-process nucleosynthesis in AGB stars at solar metallicity. • Comparison with spectroscopic data of intrinsic and extrinsic AGBs

  3. Formation of Heavy Elements • Thermonuclear reactions A<56 • Neutron captures - slow (s-process) 105-1011 free neutrons/cm3 - rapid (r-process) 1022-1025 free neutrons/cm3

  4. s-process

  5. Core H burning Core H exhaustion and contraction of the star H-shell ignition → core contraction + envelope expansion First dredge-up Core He burning Core He exhaustion; contraction of the C-O core Degenerate C-O core + alternate burning H and He shells + He intershell + extended convective envelope Stellar evolution of low mass stars

  6. Nucleosynthesis in AGB Stars • Neutron sources: • radiative 13C(α,n)16O • convective 22Ne(α,n)25Mg • 22Ne formation: 14 N(α,γ)18F(β+,ν)18O(α,γ) 22Ne • 13C formation: 12C(p, γ) 13 N(β+,ν)13C(p, γ)14 N Busso, Gallino &Wasserburg ARA&A 1999

  7. Variuos 13C pocket efficiencies, same metallicity hs(Ba, La, Cs, Nd,Sm) ls(Sr, Y, Zr) Pb

  8. IRAS 0713+1005

  9. 2 1 1 1 2 2 2 1 Extrinsic AGBs

  10. HD 123585 Allen & Barbuy 2006

  11. Conclusions • comparison between theoretical models and spectroscopic observations for the element abundances of 30 barium stars and 12 post-AGB stars • models succesfully reproduce the observational data

More Related