Abstract
In models with a larger central mass condensation, eigenfrequencies of lower-order g +-modes may become larger than the eigenfrequency of the f-mode and even than eigenfrequencies of lower-order p-modes. Consequently, modes may display a dual character: a character of g +-mode in the G-region and a character of p-mode in the A-region. In sequences of stellar models with an increasing central mass condensation, modes with a dual character bump against each other. A close analogy exists between mode bumping and the avoided crossing of modes of a double oscillator. Therefore, a theory of the avoided crossing of spheroidal modes in stars is presented. The avoided crossings of non-radial modes have implications for the identifications of these modes. The phenomenon of the strange radial modes is explained in terms of avoided crossings between radial modes in stars with surface layers in which the zone of the partial ionization of hydrogen acts as a potential barrier.
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Smeyers, P. (2010). Classification of the Spheroidal Normal Modes (continued). In: Linear Isentropic Oscillations of Stars. Astrophysics and Space Science Library, vol 371. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-13030-4_12
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