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Paper: |
The s-Process Elemental Distribution in an s-Enhanced Extremely
Metal-Poor Binary |
Volume: |
445, Why Galaxies Care about AGB Stars II: Shining Examples and Common Inhabitants |
Page: |
51 |
Authors: |
Peterson, R. C. |
Abstract: |
The abundances of s-process elements in the extremely metal-poor binary
HE 0336+0113 are derived by calculating synthetic spectra for each of
its components, co-adding them with a velocity offset of 15 km s-1,
and comparing to the observed Keck HIRES spectrum. The two
components, both unevolved, are found to have the same abundances.
Their iron-to-hydrogen ratio is 1/200 solar, [Fe/H] = –2.3. Carbon
and heavy s-process elements are enhanced to solar levels; nitrogen,
sodium, and the light s-process elements are enhanced by more than a
factor of ten, but magnesium has the normal factor-of-three halo
enhancement. This further constrains main s-process element
nucleosynthesis at low metallicity, as it occurred in the now-invisible
third companion (a more massive, evolved star) while on the asymptotic
giant branch. |
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