2016ApJ...818L..13W

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 observations. In this Letter, we adopt the χ²-minimization method but only use the observed high-precision oscillation to constrain theoretical models for solar-like oscillating 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 τ₀ is the only global parameter that can be accurately measured by the χ_v²-matching method between observed frequencies and theoretical model calculations. We obtain τ₀ = 4601.5_–8.3^+4.4 s. In addition, we analyze the distribution of χ_v²-minimization models (CMMs) and find that the distribution range of CMMs 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.