Since the light level changes from

     peak  =  about 1.000

     dip   =  about 0.992

  the depth of the dip is


           depth  =  1.000 - 0.992  =  0.008   

                                    =  0.8 percent

 
  The depth is related to the size of the planet as follows:


        area of planet      pi * (radius of planet)^2
        --------------  =   -------------------------   =   depth
        area of star        pi * (radius of star)^2


  So

                                   2
               ( radius of planet )
               ( ---------------- )     =    depth
               ( radius of star   )

 
  And we can solve for the ratio of planet's radius to star's radius:


                 radius of planet
                ------------------    =    sqrt ( depth )  
                  radius of star 

                                      =    sqrt ( 0.008 )


                                      =    0.089

  So

               ( radius of planet )   =    0.089 * (radius of star)

  
  If the star is like our Sun, then

               ( radius of planet )   =    0.089 * (6.96 x 10^5  km)

                                      =    62,000 km


  which is roughly the size of Saturn.