Large frequency separation
= Large frequency separation
{title2=$\Delta\nu\simeq(2\int_0^Rdr/c_s)^{-1}$}
The leading separation between successive high-order low-degree <stellar acoustic mode> frequencies is the inverse round-trip acoustic travel time, $\Delta\nu\simeq[2\int_0^Rdr/c_s]^{-1}$. For homologous stars it scales approximately as $(M/R^3)^{1/2}$ and therefore measures mean density.