FM17p.01 — Scaling of oscillation frequencies in rotating stars

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Aug 10th at 6:00 PM until 6:00 PM

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Author(s): Diego Castaneda1, Robert Deupree1

Institution(s): 1. Saint Mary's University

We have studied oscillation frequencies of two-dimensional uniformly rotating zero-age main sequence stellar models in the delta Scuti mass range. Four different masses were included. We identified 370 p and g axisymetric modes for each non-rotating model and then traced their evolution as the rotational velocity was increased. For each mass we considered a rotation sequence of ten models, with the largest rotation rate being about 200 km s-1. We constrained the models of a given rotation to have the same surface shape for all masses. This shape can be characterized for uniform rotation by the ratio between the polar and the equatorial radii. We find that scaling relationships exist among the oscillation frequencies calculated for models with the same shape but different masses. For p modes, this scaling closely follows the period root-mean-density relation found in spherical stars. The g modes also scale between models of the same shape, with the scaling reflecting the growth of the convective core in mass as the stellar mass increases. These scaling relationships can be particularly useful in finding specific stellar models to match the oscillation frequencies of individual stars.