Comparison of current models for Hot Jupiters to the sample of transiting exoplanets

TL;DR

This study compares current models of Hot Jupiters with the observed sample of transiting exoplanets, analyzing their mass-radius relations and Safronov numbers to improve understanding of their formation and internal structure.

Contribution

It provides the first comprehensive comparison of observed transiting exoplanets with theoretical models, highlighting discrepancies and potential classifications based on Safronov numbers.

Findings

Safronov numbers show two classes, with some above the formal Class I definition.

Mass-radius relations challenge models with large core masses (e2
0e299 Mb5f8).

Inflated planets may resemble brown dwarf models rather than standard ESP models.

Abstract

A growing number (over 100!) of extra-solar planets (ESPs) have been discovered by transit photometry, and these systems are important because the transit strongly constrains their orbital inclination and allows accurate physical parameters for the planet to be derived, especially their radii. Their mass-radius relation allows us to probe their internal structure. In the present work we calculate Safronov numbers for the current sample of ESP and compare their masses and radii to current models with the goal of obtaining better constrains on their formation processe. Our calculation of Safronov numbers for the current TESP sample does show 2 classes, although about 20% lie above the formal Class I definition. These trends and recent results that argue against a useful distinction between Safronov classes are under further investigation. Mass-radius relations for the current sample of TESP are inconsistent with ESP models with very large core masses (\geq 100 M\oplus). Most TESP with radii near 1RJ are consistent with models with no core mass or core masses of 10 M\oplus . The inflated planets, with radii \geq 1.2 RJ are not consistent with current ESP models, but may lie along the lower end of models for brown dwarfs. Although such models are nascent, it is important to establish trends for the current sample of ESP, which will further the understanding of their formation and evolution.