The Super Earth-Cold Jupiter Relations

TL;DR

This study reveals a strong correlation between super Earths and cold Jupiters around Sun-like stars, suggesting they share similar origins and are often found together, with implications for planetary system formation theories.

Contribution

It provides the first comprehensive statistical analysis linking super Earths and cold Jupiters, demonstrating their frequent co-occurrence and shared formation conditions.

Findings

Cold Jupiters are three times more common around super Earth hosts.

Nearly 90% of cold Jupiters are accompanied by super Earths.

Systems like our own, with cold Jupiters but no super Earths, are very rare.

Abstract

We report relations between inner ($<1$ au) super Earths (planets with mass/radius between Earth and Neptune) and outer ($>1$ au) giant planets (mass $>0.3~M_{\rm J}$, or cold Jupiters) around Sun-like stars, based on data from both ground-based radial velocity (RV) observations and the Kepler mission. We find that cold Jupiters appear three times more often around hosts of super Earths than they do around field stars. Given the prevalence of the super Earth systems, their cold Jupiters can account for nearly all cold Jupiters. In other words, cold Jupiters are almost certainly ($\sim90\%$) companied by super Earths. A few corollaries follow: (1) around metal-rich ([Fe/H]$>0.1$) stars, the fraction of super Earths with cold Jupiters can rise to $60\%$ or higher; (2) the inner architecture can be strongly impacted by the outer giant and we report some observational evidence for this; (3) planetary systems like our own, with cold Jupiters but no super Earths, should be rare ($\sim1\%$). The strong correlation between super Earths and cold Jupiters establish that super Earths and cold Jupiters do not compete for solid material, rather, they share similar origins, with the cold Jupiter formation requiring a somewhat more stringent condition. Lastly, we propose a few immediate observational tests of our results, using ground-based RV observations and ongoing/planned space missions.