The exact mathematical expression for an arbitrary nth-order stellar
hydrodynamic equation is explicitly obtained depending on the central
moments of the velocity distribution. In such a form the equations are
physically meaningful, since they can be compared with the ordinary hy-
drodynamic equations of compressible, viscous fluids. The equations are
deduced without any particular assumptions about symmetries, steadi-
ness, or particular kinematic behaviours, so that they can be used in
their c...
The exact mathematical expression for an arbitrary nth-order stellar
hydrodynamic equation is explicitly obtained depending on the central
moments of the velocity distribution. In such a form the equations are
physically meaningful, since they can be compared with the ordinary hy-
drodynamic equations of compressible, viscous fluids. The equations are
deduced without any particular assumptions about symmetries, steadi-
ness, or particular kinematic behaviours, so that they can be used in
their complete form, and for any order, in future works with improved
observational data. Also, in order to work with a finite number of equa-
tions and unknowns, which would provide a dynamic model for the stel-
lar system, the nth-order equation is needed to investigate in a more
general way the closure conditions, which may be expressed in terms of
velocity distribution statistics, as it is shown in a case example.