Equation of state of ammonia

[摘要] Ammonia and water are critical components of extraterrestrial bodies, determining the density and physical properties of the Outer Planets, their moons, and of extrasolar planets. Ammonia is unusual in having a high heat capacity relative to other molecular species. Equations of state (EOS) are presented for ammonia and for mixtures of ammonia and water. Their properties are discussed in terms of chemical compositions that evolve as pressure and temperature are varied. The NH4OH hydrate of ammonia is known to exist as a separate molecular species at pressures above about 5 GPa, and an effort was made to include reaction between NH3and H2O in the mixture EOS. The EOS are suitable for calculating structures of icy planets and exoplanets, and of impacts. mass-radius relations which bound the possible interpretations of composition and structure for extraterrestrial bodies of unknown composition, such as exoplanets.

[发布机构] Los Alamos National Laboratory, Los Alamos; NM; 87544, United States^1;Lawrence Livermore National Laboratory, Livermore; CA; 94550, United States^2

[关键词] Chemical compositions;Critical component;Equation of state;Extraterrestrial bodies;High heat capacity;Molecular species;Outer planets;Pressure and temperature