 Specific angular momentum

The specific angular momentum is angular momentum per unit mass, $\mathbf{h}=\mathbf{r}\times \mathbf{v}$. For a planar Kepler orbit its magnitude is $h=r^2\dot{\theta }=\sqrt{\mu a(1-e^2)}$.

Specific angular momentum is a physical quantity that represents the angular momentum of an object per unit mass. It is commonly denoted by the symbol \( h \) or \( \mathbf{l} \), depending on the context. Specific angular momentum is useful in orbital mechanics and dynamics to analyze the motion of bodies in gravitational fields, such as planets, satellites, and spacecraft.