Published online by Cambridge University Press: 18 February 2014
Standard models of low-mass core helium burning stars typically give an asymptotic l=1 g-mode period spacing well below that inferred from observed mixed modes. We find that most physical uncertainties, such as mixing beyond the fully convective core, are not significant enough to be responsible for such a discrepancy. The solution to the problem may lie in a deviation of structure away from its canonical form, such as a more massive H-exhausted core, which we briefly explore here.