Classification of exoplanets according to density

TL;DR

This paper classifies exoplanets into three density-based groups using probability distribution analysis, identifying populations of gas/ice giants, super-Earths, and brown dwarfs, revealing diverse planetary densities.

Contribution

The study introduces a density-based classification of exoplanets into three distinct populations using statistical modeling of their density distribution.

Findings

Identification of three main density populations: ~0.7, 7, and 30 g/cc.

Recognition of extreme density planetary objects.

Correlation of density groups with planetary types.

Abstract

Considering probability distribution as a function of the average density $\bar{\rho}$ computed for 424 extrasolar planets we identify three log-normal Gaussian population components. The two most populous components at $\bar{\rho}\simeq0.7$ g/cc and $\bar{\rho}\simeq7$ g/cc are the ice/gas giants and iron/rock super-Earths, respectively. A third component at $\bar{\rho}\simeq30$ g/cc is consistent with brown dwarfs, i.e., electron degeneracy supported objects. We note presence of several extreme density planetary objects.