Better estimating the core mass of Jupiter

Abstract

The mass of Jupiter’s core is currently estimated to be between 5 and 20E⊕, which leaves the core mass as a significant unknown quantity when examining the solar system. The two primary theories that address the formation of giant planets such as Jupiter, are Core Accretion (CA) and Disc Instability (DI). CA predicts that the core mass should be between 15 − 20E⊕, and DI predicts that the core mass should be between 5 − 10E⊕. Since both predictions overlap with the current estimates, neither method can be confirmed as the one used to form Jupiter. Through Modules of Experiments in Stellar Astrophysics (MESA), a series of models of Jupiter was created with changes in their core mass in 0.5E⊕ intervals within the current estimate. Using GYRE, a stellar oscillation code, the model’s p-modes and g-modes were analyzed. Upon examination of p-modes, it was found that changes in the core had no significant effect on their oscillations per theoretical predictions. Several models exhibited irregular behaviours in their g-modes, showing higher than average percentage of frequencies with positive mode work and normalized growth rates (η). The physical characteristics of these irregular models were examined and found that the sound speed varied in regions less than 0.40 Jupiter radii. Additionally, period spacings of these models found the spacings to be regular and dips in the spacing, likely being caused by changes in the local molecular weight. Variations in regions of g-mode oscillations with core mass were found between 0.2 and 0.5 Jupiter radii, which further indicates that the core mass is affecting the g-mode oscillations and could be causing physical changes in the models. This research was not able to fully examine the exact differences in the interior structures that might be causing these irregular behaviours to occur but should be examined in the future. The results of this research remain inconclusive in determining better estimations for the core mass of Jupiter but can act as a foundation for future esearchers to continue.