Q:  What is the gravitational acceleration of star A?

                           G m_B
               accel  =   ----------   
                             a^2


                      =    0.69  m/s^2


  Q:  What is the centripetal acceleration of star A?

                             (v_A)^2                 (v_A)^2 
               accel  =   -----------   =   -----------------------------
                              R_A             a * [ m_B / (m_A + m_B) ]


                              (v_A)^2
                      =    ------------------
                             8.70 x 10^(8) m



  Q:  Solve for the velocity of star A.

                                     G * (m_B)^2
                 v_A   =    sqrt ( ------------------ )
                                     a * (m_A + m_B)


 
                       =    2.45 x 10^(4) m/s   =   24.5 km/s