Rigid Body

Two bodies of masses $m_1$ and $m_2$ move under the action of their mutual gravitation.
Let $\vec{r}_1$ and $\vec{r}_2$ be the position vectors in a space-fixed coordinate system, and $\vec{r}=\vec{r}_1-\vec{r}_2$.
Find the equation of motion for $\vec{r}_1$, $\vec{r}_2$ and $\vec{r}$ in the center-of-mass system.