The radial dependences of ﹩{M}_{p,\mathrm{transI}}﹩ and ﹩{M}_{p,\mathrm{transII}}﹩, and the resulting mass region in which the heavy-element content trend can be reproduced (see the red shaded region). The light green dots denote observed exoplanets listed in exoplanets.org, while the purple squares are the samples of T16. For reference, the solar system planets are shown by the black triangles.