The role of rotation on Petersen Diagrams. II The influence of near-degeneracy - AstrophysicsReport as inadecuate




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Abstract: In the present work, the effect of near-degeneracy on rotational Petersendiagrams RPD is analysed. Seismic models are computed considering rotationeffects on both equilibrium models and adiabatic oscillation frequenciesincluding second-order near-degeneracy effects. Contamination of coupledmodes and coupling strength on the first radial modes are studied in detail.Analysis of relative intrinsic amplitudes of near-degenerate modes reveals thatthe identity of the fundamental radial mode and its coupled quadrupole pair arealmost unaltered once near-degeneracy effects are considered. However, for thefirst overtone, a mixed radial-quadrupole identity is always predicted. Theeffect of near-degeneracy on the oscillation frequencies becomes critical forrotational velocities larger than 15-20 km-s, for which large wriggles in theevolution of the period ratios are obtained up $10^{-2}$. Such wriggles implyuncertainties, in terms of metallicity determinations using RPD, reaching up to0.50 dex, which can be critical for Pop. I HADS High Amplitude \dss. In termsof mass determinations, uncertainties reaching up to 0.5 M sun are predicted.The location of such wriggles is found to be independent of metallicity androtational velocity, and governed mainly by the avoided-crossing phenomenon.



Author: J. C. Suarez, R. Garrido, A. Moya

Source: https://arxiv.org/







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