Polytropic constant
= Polytropic constant
{title2=$K$}
The coefficient $K$ in a <polytropic equation of state> $p=K\rho^\Gamma$. It is spatially constant for one simple <polytrope>, but need not stay constant between different equilibrium models. For a fixed-composition <ideal gas> with $\Gamma$ equal to its <adiabatic index>, $K$ parametrizes <specific entropy>: $s=c_v\ln K+\text{constant}$ with a suitable dimensional reference inside the logarithm.