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| Paper: |
Progress in high S/N spectroscopy and its importance for stellar modelling |
| Volume: |
40, Inside the Stars, IAU Colloquium 137 |
| Page: |
108 |
| Authors: |
Nissen, P. E. |
| Abstract: |
The study examines recent advances in high S/N spectroscopy with particular emphasis on new data for the abundances of chemical elements of importance for the modeling of stellar interiors. Among normal A-type stars, with the exception of A(m) and A(p) stars, large deviations from solar abundance ratios occur with interesting anticorrelations of the abundances of C and Si. It is inferred that diffusion processes and/or gas-dust separation of the chemical elements in the protostellar cloud play an important role. For F and G main-sequence stars the atmospheric abundance ratios of elements heavier than boron probably represent the original interior compositions. For metal-poor stars the abundance ratios are nonsolar, and overabundances of oxygen and other alpha-elements have important effects on stellar opacities and energy generation. |
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