On the hyperbolicity of a model with 30 moments for ultrarelativistic gases

An exact macroscopic extended model for ultrarelativistic gases, with an arbitrary number of moments, is present in literature. Here we exploit equations determining wave speeds for the model with 30 independent fields. We find interesting results; for example, the whole system for their determination can be split in some independent subsystems, some wave speeds are expressed by square roots of rational numbers, but not all of them. Moreover these wave speeds for the macroscopic model are the same of those in the kinetic model.