  The pileup of planets at periods of roughly one year and beyond is actually a
bimodal peak with a wide, sharp gap splitting the peak of the pileup in a major
population of large planets. Consisting of nearly 40\% of planets with periods
past 200 days, the periods of the planets of metal-rich stars like the sun in
surface gravity which do not have a stellar companion show two strong peaks
separated by a sparsely populated region. Monte Carlo tests show that this
structure is unlikely to occur in random distributions, and a comparison with
objects from all the other populations show that this feature is unlikely to be
due to observational effects. The peaks have their highest density next to the
gap. These two peaks are most strongly seen in single-planet systems, though
the gap persists in multiple planet systems. These features are likely
characteristic of planets with masses not too much lower than Jupiter, and
perhaps not too much higher. The presence of well-defined features in the
period distribution show that planet formation may be much more uniform than
previously expected.
