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| Paper: |
Stratification of Elements in Main-sequence CP Stars and Their
Observational Effects |
| Volume: |
462, Progress in Solar/Stellar Physics with Helio- and Asteroseismology |
| Page: |
80 |
| Authors: |
Alecian, G. |
| Abstract: |
According to the diffusion model, the observed large abundance anomalies in chemically
peculiar (CP)
stars are a consequence of chemical stratification in their atmospheres. All the
elements are affected. However, the stratification process does not only concern
the atmospheres, but also internal layers. Such a chemical stratification has
several consequences. The most obvious one is the impact on the abundance
determinations and their interpretation. Another consequence is a significant
modification of the Rosseland opacity of internal layers, due to the enhancement
of iron-peak elements. This necessarily affects the internal structure and
asteroseismic properties of these stars. Another aspect, also related to the
diffusion processes, is the consequence of the possible existence of weak
undetected magnetic fields in those of the CP stars usually considered as
non-magnetic (HgMn). This point will be discussed in the present paper and it
will be shown that such a situation is not incompatible with the diffusion
model, and moreover, could explain some recent observations of spectroscopic
variations. |
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