Quantum ion thermodynamics in liquid interiors of white dwarfs

We present an accurate analytic approximation for the energy of a quantum one-component Coulomb liquid of ions in a uniform electron background which has been recently calculated from first principles (Baiko 2019). The approximation enables us to develop in an analytic form a complete thermodynamic description of quantum ions in a practically important range of mass densities at temperatures above crystallization. We show that ionic quantum effects in liquid cores of white dwarfs (WDs) affect heat capacity, cooling, thermal compressibility, pulsation frequencies and radii of sufficiently cold WDs, especially with relatively massive helium and carbon cores.