New Insights for High-precision Asteroseismology: Acoustic Radius of KIC 6225718
Tao Wu (Yunnan Observatories, Chinese Academy of Sciences), Yan Li (Yunnan Observatories, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011; Key Laboratory for Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011, China)

Asteroseismology is a powerful tool for probing stellar interiors and determining stellar fundamental parameters. In previous works, the χ2-minimization method is usually used to find the best-matching model to characterize obser- vations. In the present work, we adopt the χ2-minimization method but only use the observed high-precision oscillation to constrain theoretical models for solar-like oscillation star KIC 6225718, which is observed by the Kepler satellite. We also take into account the influence of model precision. Finally, we find that the time resolution of stellar evolution cannot be ignored in high-precision asteroseismic analysis. Based on this, we find the acoustic radius τ0is the only global parameter that can be accurately measured by the χ2-matching method between observed frequencies and the- oretical model calculations for a pure p-mode oscillation star. We obtain τ0= 4601.5+4.4/−8.3 s. In addition, we analyze the distribution of χ2-minimization models and find that its distribution range is slightly enlarged by some extreme cases, which possess both a larger mass and a higher (or lower) heavy element abundance, at the lower acoustic radius end.