  Core Accretion (CA), the de-facto accepted theory of planet formation,
requires formation of massive solid cores as a prerequisite for assembly of gas
giant planets. The observed metallicity correlations of exoplanets are puzzling
in the context of CA. While gas giant planets are found preferentially around
metal-rich host stars, planets smaller than Neptune orbit hosts with a wide
range of metallicities. We propose an alternative interpretation of these
observations in the framework of a recently developed planet formation
hypothesis called Tidal Downsizing (TD). We perform population synthesis
calculations based on TD, and find that the connection between the populations
of the gas giant and the smaller solid-core dominated planets is non linear and
not even monotonic. While gas giant planets formed in the simulations in the
inner few AU region follow a strong positive correlation with the host star
metallicity, the smaller planets do not. The simulated population of these
smaller planets shows a shallow peak in their formation efficiency at around
the Solar metallicity. This result is driven by the fact that at low
metallicities the solid core's growth is damped by the scarcity of metals,
whereas at high metallicities the fragments within which the cores grow
contract too quickly, cutting the core's growth time window short. Finally,
simulated giant gas planets do not show a strong host star metallicity
preference at large separations, which may explain why one of the best known
directly imaged gas giant planet systems, HR 8799, is metal poor.
