2021ApJ...922..138G

Asteroseismology is a powerful tool to infer the details of the inner chemical structure of white dwarfs. Using the nine observed frequencies of HS 0507+0434B, we explore the influence of the inner chemical profile on the pulsation periods. Based on the evolutionary C/O profile, we modify slightly the C/O core profile and make an asteroseismic analysis for HS 0507+0434B. We find that the trapped mode with the period of 445.3 s is mainly affected by the hydrogen and helium mass fraction. The inner C/O core profile has an influence on all modes extending into the inner core. When we use the iteration method with the optimal C/O core profile, the fit between the theoretical periods and observed ones is significantly improved. For the best-fitting model with the optimal parametric C/O core, there is a smaller C/O ratio and a smaller overshooting zone in the stellar interior. The fundamental parameters of the model with the optimal C/O core are M_*/M_☉ ∼ 0.710 ± 0.005, T_eff ∼ 12570 ± 106K, logM_H/M_*∼-8.01±0.08, and logM_He/M_*∼-2.51±0.08.