2007A&A...472..571Y

The purpose of this work is to investigate the characteristics of a new frequency separation of stellar p-modes. Frequency separations are deduced from the asymptotic formula of stellar p-modes. Then, using the theoretical adiabatic frequencies of stellar model, we compute the frequency separations. A new separation σ_l–1l+1(n), which is similar to the scaled small separation d_ll+2(n)/(2l+3), is obtained from the asymptotic formula of stellar p-modes. The separations σ_l–1l+1(n) and d_ll+2(n)/(2l+3) have the same order. And like the small separation, σ_l–1l+1(n) is mainly sensitive to the conditions in the stellar core. However, with the decrease in the central hydrogen abundance of stars, the separations σ₀₂ and σ₁₃ deviate more and more from the scaled small separation. This characteristic could be used to extract the information on the central hydrogen abundance of stars.