5.

Two stars of mass m=1.70 and M=10.0 (in units of solar masses) separated by a distance d=5.00 (in units of AU, the earth-sun distance) revolve in circular orbits about their (common) center of mass as shown in the figure below.

\f4 7 1 3 11 G ( M +m ) m a (M+m ) Solar May = 2X1050 1 Astonomical Unit = 1. 496 x 10 ' G= 16:67 X 10 M T = 2 X 3. 14 x / 5 X 1 4 9 6 X10m P (1 . 6 7 X 10 m / 1 1 7 + 10 0 ) x 2 x 10 kq T = 2 . 06 x 10 8 Seconds 36 5 x 2 4 x 60 * 60 =) E1 6 - T = 6:52 years