# Observational evidence for two distinct giant planet populations

## TL;DR

This study provides observational evidence suggesting the existence of two distinct populations of giant planets, differentiated by their mass and host star properties, implying potentially different formation mechanisms.

## Contribution

It identifies a possible bifurcation in giant planet populations around 4 M_Jup, linking this to different formation processes and host star characteristics.

## Key findings

- Two populations of giant planets with a mass break at ~4 M_Jup.
- Stars hosting more massive planets tend to be more metal-poor and massive.
- Different formation mechanisms may be responsible for the two populations.

## Abstract

Analysis of the statistical properties of exoplanets, together with those of their host stars, are providing a unique view into the process of planet formation and evolution. In this paper we explore the properties of the mass distribution of giant planet companions to solar-type stars, in a quest for clues about their formation process. With this goal in mind we studied, with the help of standard statistical tests, the mass distribution of giant planets using data from the exoplanet.eu catalog and the SWEET-Cat database of stellar parameters for stars with planets. We show that the mass distribution of giant planet companions is likely to present more than one population with a change in regime around 4\,M$_{Jup}$. Above this value host stars tend to be more metal poor and more massive and have [Fe/H] distributions that are statistically similar to those observed in field stars of similar mass. On the other hand, stars that host planets below this limit show the well-known metallicity-giant planet frequency correlation. We discuss these results in light of various planet formation models and explore the implications they may have on our understanding of the formation of giant planets. In particular, we discuss the possibility that the existence of two separate populations of giant planets indicates that two different processes of formation are at play.