A binary star consists of two stars A and B that orbit one another, as illustrated below.
The stars are in circular orbits with the centers of both orbits at point P, a distance 
from the centre of star A. The separation of the centres of the stars is 
. The period of the orbit of the stars about point P is 4.0 years and the distance is 
. Determine the mass 
of star B.
.
