Characteristics of solar-like oscillations of secondary red-clump stars

We calculated the populations of core-helium-burning (CHeB) stars and found that secondary red-clump (SRC) stars can form a SRC peak in the distributions of the frequency of maximum seismic amplitude (nu(max)) and mean large-frequency separation (Delta nu) of CHeB stars when metallicity Z >= 0.02. The nu(max) and Delta nu of CHeB stars are dependent not only on He-core mass but also on H-shell burning. The SRC peak is composed of CHeB stars with mass roughly between the critical mass M-HeF and M-HeF + 0.2, while He-core mass is between about 0.33 and 0.36 M-circle dot. The location of the SRC peak can be affected by the mixing-length parameter alpha, metallicity Z and overshooting parameter delta(ov). A decrease in alpha or increase in Z or delta(ov) leads to a movement of the SRC peak towards a lower frequency. The change in Z and alpha only slightly affects the value of M-HeF, but the variation in delta(ov) can affect the value of M-HeF significantly. Thus the SRC peak might aid in determining the value of M-HeF and calibrating delta(ov). In addition, the effects of convective acceleration of SRC stars and the decrease in the nu(max) of 'semidegenerate' stars with mass result in the appearance of a shoulder between about 40 and 50 mu Hz in the nu(max) distribution. However, the convective acceleration of stars with M < M-HeF leads to a deficit in the nu(max) distribution between about 9 and 20 mu Hz. Moreover, the value of the parameter b of the relation between nu(max) and Delta nu for populations with M > M-HeF is obviously larger than that for populations with M < M-HeF.