Testing Bimodal Planet Formation

We suggest that the observed break in giant-planet frequency as a function of host metallicity at Z=0.02 may be a reflection of bimodal planet formation. We search for signatures of this bimodality in the distributions of the planet eccentricities, periods, masses, and multiplicity. However, the low-metallicity sample is at present too small to test for any but the most severe differences in these two putative populations.