distance d       orbital radius     central mass        
    (Mpc)                r                M
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                           3                   7
     5              25 x 10  AU        2.8 x 10   solar      ___________

                          15                   37
                  3.7 x 10   m         5.6 x 10   kg


                           3                   7
     7              35 x 10  AU        3.9 x 10  solar       ___________

                          15                   37
                  5.2 x 10   m         7.9 x 10   kg


                           3                   7
    10              50 x 10  AU        5.6 x 10  solar       ___________

                          15                   37
                  7.5 x 10   m        11.2 x 10   kg


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