5:15 PM - 6:45 PM
[MGI29-P03] The Equation of State Dependence of Simulations of the Formation of Proto-Uranian Disks by Giant Impacts
Keywords:EOS, SPH, Uranus
The current Uranus, its major satellites, and rings have an inclination of roughly 98 degrees. One hypothesis proposed to explain this feature is the giant impact hypothesis. This suggests that Uranus' axis was tilted by a giant impact, and the satellites were formed from the disk generated by the collision. Following this hypothesis, fluid numerical simulations of giant impacts have been conducted using the Smoothed Particle Hydrodynamics (SPH) method (e.g., Slattery et al. 1992; Kurosaki & Inutsuka 2019; Kegerreis et al. 2018; Reinhardt et al. 2020). These simulations generally predicted a disk that is heavy, compact. This was considered contradictory to Uranus' current satellite system. However, research by Ida et al. (2020) showed that the contradiction in the mass and size of the disk could be resolved by the evolution of the disk up to the recondensation of ice. Nevertheless, there remains an incomplete resolution to the problem of the amount of rock contained in the disk, as it varies in each simulation, and Uranus' satellites exhibit a composition richer in rock compared to Uranus itself (approximately 30-50% by mass). This difference is believed to be due to variations in the equations of state used in the simulations.
Therefore, in this study, we conducted simulations of giant impacts on Uranus, an ice giant, using three different equations of state (ANEOS/SESAME, Tillotson, and the model by Hubbard & MacFarlane (1980)), which have been used in previous studies. The simulations were performed using the Satndard SPH and the Density Independent SPH method (Saitoh & Makino, 2013; Hosono et al., 2013). In this presentation, we focus on the effects of differences in equations of state, particularly on the ice-to-rock mass ratio of the formed disk and the total mass of rock.
Therefore, in this study, we conducted simulations of giant impacts on Uranus, an ice giant, using three different equations of state (ANEOS/SESAME, Tillotson, and the model by Hubbard & MacFarlane (1980)), which have been used in previous studies. The simulations were performed using the Satndard SPH and the Density Independent SPH method (Saitoh & Makino, 2013; Hosono et al., 2013). In this presentation, we focus on the effects of differences in equations of state, particularly on the ice-to-rock mass ratio of the formed disk and the total mass of rock.