Consider a star of mass \( m_{2} \) \( \text{kg} \) revolving in a circular orbit around another star of mass \( m_{1} \) \( \text{kg} \) with \( m_{1} \gg m_{2} \). The heavier star slowly acquires mass from the lighter star at a constant rate of \( \gamma \) \( \text{kg/s} \). In this transfer process, there is not other loss of mass. If the separation between the centres of the stars is \( r \), then its relative rate of change \( \dfrac{1}{r}\dfrac{dr}{dt} \) (in \( \text{s}^{-1} \)) is given by:
