M. S. Cunha, I. M. Brandão
Abstract
Stars slightly more massive than the Sun develop small convective cores during their main sequence phase of evolution. The edges of these convective cores are associated with rapid variations in the sound speed which influence the frequencies of acoustic oscillations. In this work we use an asymptotic analysis that is valid near the turning point of the oscillations, to derive the signature that tiny convective cores, such as those expected in main-sequence solar-like pulsators, produce in the oscillation frequencies. Moreover, we present a seismic diagnostic tool that is capable of isolating essential properties of that signature. The analysis presented here is an extension of that published by Cunha & Metcalfe (2007). In particular, in the current work the functional form adopted in the modelling of the sharp variation in sound speed at the edge of the core is more realistic. That results in an improved capability to extract the size of the sharp variation in sound speed at the edge of the core, a property that depends on the physical processes of mixing and diffusion taking place in that region of the star.
Keywords
stars: interiors - stars: oscillations
Astronomische Nachrichten
Volume 331, Number 9-10, Page 925
2010 December
