Giant planet/star metallicity (non)-correlation

A good question:

Teske et al. "Do Metal-Rich Stars Make Metal-Rich Planets? New Insights on Giant Planet Formation from Host Star Abundances"
https://arxiv.org/abs/1912.00255

From the abstract:

Quote :

Surprisingly, we find no clear correlation between stellar metallicity and planetary residual metallicity (the relative amount of metal versus that expected from the planet mass alone), which is in conflict with common predictions from formation models. We also find a potential correlation between residual planet metals and stellar volatile-to-refractory element ratios. These results provide intriguing new relationships between giant planet and host star compositions for future modeling studies of planet formation.

HAT-P-18 appears to be an outlier to the potential trend with volatile-to-refractory element abundances.