4:00 PM - 4:15 PM
[PPS06-23] Migration of the Snow Line due to Shock Heating Caused by Giant Planets in Protoplanetary Disks
Keywords:hydrodynamics, protoplanetary disks, planet-disk interactions
It is widely believed that rocky planets, including Earth, formed in regions inside the snow line (the orbit where ice sublimates) in protoplanetary disks. Understanding the temperature structure of the protoplanetary disk and the location of the snow line is essential for understanding the formation of rocky planets. Recent models for the disk temperature structure based on non-ideal magnetohydrodynamics (Mori et al. 2021; Kondo et al. 2023) predict a lower disk temperature and an inner snow line than the traditional viscous disk models do. This raises the question of whether solar-system rocky planets including Earth formed at their current orbits.
In this study, we focus on shock heating caused by giant planets, a previously overlooked disk heating source. The isotopic dichotomy of solar system materials (e.g., Warren 2011; Kruijer et al. 2020) suggests that Jupiter may have formed early in the solar nebula. When such a giant planet exists in a disk, spiral density waves propagate through the disk. As these spiral density waves become shocks, they heat the disk. Ziampras et al. (2020) showed through hydrodynamic simulations of disks with planets that, when a Jupiter-mass planet is located within a few astronomical units (au) from the star, the temperature increases both near the planet and in regions inside the planet’s orbit. Ono et al. (2025) calculated the disk heating rate caused by spiral shockwaves near the planet's orbit by measuring the increase in entropy across the shock. However, the shock heating rate in the region well interior to the giant planet’s orbit has not been explored.
In this study, we investigate the role of spiral shocks created by giant planets in the temperature structure of the inner disk and the location of the snow line. First, we perform 2D hydrodynamic calculations for a disk with a giant planet, extending the calculation region up to one-tenth of the planet's orbital radius, and measure the heating rate caused by spiral shocks in the inner disk. Then, using the obtained shock heating distribution, we model the radial temperature distribution of the disk with inefficient accretion heating and examine whether shock heating by the giant planet can change the snow line location.
The results of the 2D hydrodynamic calculations show that more than five spiral arms exist inside the giant planet’s orbit. For example, when the giant planet is located at a 5 au orbit (the current orbit of Jupiter), the quaternary and quinary waves contribute the most to disk heating at the 1 au (the current Earth orbit). The sum of the shock heating rates from the primary to the quinary waves can be approximated by a simple power function of the distance from the planet's orbit and its mass. Our temperature distribution model calculations reveal that if a Jupiter-mass planet forms at 5 au in a disk, the snow line migrates outside the 1 au orbit due to disk heating from the quaternary and quinary waves. This suggests that Jupiter that formed early in the solar nebula might have enabled the formation of solar-system rocky planets around their current orbits.
In this study, we focus on shock heating caused by giant planets, a previously overlooked disk heating source. The isotopic dichotomy of solar system materials (e.g., Warren 2011; Kruijer et al. 2020) suggests that Jupiter may have formed early in the solar nebula. When such a giant planet exists in a disk, spiral density waves propagate through the disk. As these spiral density waves become shocks, they heat the disk. Ziampras et al. (2020) showed through hydrodynamic simulations of disks with planets that, when a Jupiter-mass planet is located within a few astronomical units (au) from the star, the temperature increases both near the planet and in regions inside the planet’s orbit. Ono et al. (2025) calculated the disk heating rate caused by spiral shockwaves near the planet's orbit by measuring the increase in entropy across the shock. However, the shock heating rate in the region well interior to the giant planet’s orbit has not been explored.
In this study, we investigate the role of spiral shocks created by giant planets in the temperature structure of the inner disk and the location of the snow line. First, we perform 2D hydrodynamic calculations for a disk with a giant planet, extending the calculation region up to one-tenth of the planet's orbital radius, and measure the heating rate caused by spiral shocks in the inner disk. Then, using the obtained shock heating distribution, we model the radial temperature distribution of the disk with inefficient accretion heating and examine whether shock heating by the giant planet can change the snow line location.
The results of the 2D hydrodynamic calculations show that more than five spiral arms exist inside the giant planet’s orbit. For example, when the giant planet is located at a 5 au orbit (the current orbit of Jupiter), the quaternary and quinary waves contribute the most to disk heating at the 1 au (the current Earth orbit). The sum of the shock heating rates from the primary to the quinary waves can be approximated by a simple power function of the distance from the planet's orbit and its mass. Our temperature distribution model calculations reveal that if a Jupiter-mass planet forms at 5 au in a disk, the snow line migrates outside the 1 au orbit due to disk heating from the quaternary and quinary waves. This suggests that Jupiter that formed early in the solar nebula might have enabled the formation of solar-system rocky planets around their current orbits.