AAS 205th Meeting, 9-13 January 2005
Session 34 Stellar Structure and Evolution
Oral, Monday, January 10, 2005, 10:00-11:30am, Royal Palm 4-6

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[34.04] Updated radiative accelerations from the Opacity Project.

F. Delahaye (The Ohio State University)

Microscopic diffusion processes (such as radiative levitation and gravitational settling/thermal diffusion) in the outer layers of stars are important because they may give rise to surface abundance anomalies. While many previous works on radiative acceleration used atomic data from the Opacity Project (OP) and from OPAL, most of stellar evolutionary codes including radiative levitation to date have used atomic data from the OPAL group. We previously reported differences in radiative accelerations (grad) derived from prior OP data with those computed from OPAL. I will present a comparison using the Updated opacities from OP with the previous version of OP data as well as with OPAL results.In light of the significant differences in the inferred acceleration rates, theoretical errors should be taken into account when comparing models with observations. The implications for stellar evolution will be discussed. The sensitivity of grad to the atomic physics may provide a useful test of different opacity sources. Partial support is provided by the CNRS (Observatoire de Meudon).

The author(s) of this abstract have provided an email address for comments about the abstract: delahaye@astronomy.ohio-state.edu

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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.