California Legacy Survey. II. Occurrence of Giant Planets beyond the Ice Line

We used high-precision radial velocity measurements of FGKM stars to determine the occurrence of giant planets as a function of orbital separation spanning 0.03-30 au. Giant planets are more prevalent at orbital distances of 1-10 au compared to orbits interior or exterior of this range. The increase in planet occurrence at similar to 1 au by a factor of similar to 4 is highly statistically significant. A fall-off in giant planet occurrence at larger orbital distances is favored over models with flat or increasing occurrence. We measure 14.1(-1.8)(+2.0) giant planets per 100 stars with semimajor axes of 2-8 au and 8.9(-2.4)(+3.0) giant planets per 100 stars in the range 8-32 au, a decrease in occurrence with increasing orbital separation that is significant at the similar to 2 sigma level. We find that the occurrence rate of sub-Jovian planets (0.1-1 Jupiter masses) is also enhanced for 1-10 au orbits. This suggests that lower-mass planets may share the formation or migration mechanisms that drive the increased prevalence near the water-ice line for their Jovian counterparts. Our measurements of cold gas giant occurrence are consistent with the latest results from direct imaging surveys and gravitational lensing surveys despite different stellar samples. We corroborate previous findings that giant planet occurrence increases with stellar mass and metallicity.

Automated summary

Using high-precision radial velocity measurements of FGKM stars, we found that giant planets are more prevalent at orbital distances of 1-10 au and exhibit a decrease in occurrence at larger orbital distances. Additionally, we observed an increase in occurrence of sub-Jovian planets at orbits of 1-10 au, indicating similar formation or migration mechanisms with their Jovian counterparts. Our measurements of cold gas giant occurrence align with recent results from direct imaging surveys and gravitational lensing surveys, supporting previous findings that giant planet occurrence correlates with stellar mass and metallicity.