10:45 AM - 12:15 PM
[PPS07-P27] Formation of the eccentric gap by a super-Jupiter-mass planet and its effect on the mass accretion rate of the planet
Keywords:Planet formation, Protoplanetary disks, Gas giants
A giant planet embedded in a protoplanetary disk creates a gap structure along its orbit by disk-planet interaction and grows by mass accretion through the gap. The characteristics of the gap formed in the disk strongly depend on parameters such as the mass of the planet, the viscosity and the scale height of the gas disk, which in turn affect the mass accretion rate and the orbital migration rate of the planet. Therefore, the gap formation process is important for the formation and evolution of planetary systems. In addition, recent radio observations using ALMA have revealed the existence of many protoplanetary disks with substructures such as gaps and rings, so understanding the gap formation process is also important for interpreting observation results.
Disk-planet interactions have been actively studied using numerical fluid dynamics simulations in recent years, and the width and depth of the gap formed by the planet and the mass accretion rate of the planet have been investigated in detail. However, most previous studies have focused on Jupiter-mass or lighter planets. The exoplanets discovered so far are highly diverse, and many planets heavier than Jupiter, so-called super-Jupiter-mass planets, have been discovered. When the planetary mass is several times heavier than that of Jupiter, it is known that the outer edge of the gap becomes unstable and an eccentric gap is formed, which is expected to cause a significant difference in characteristics such as surface density inside the gap. However, how the rate of mass accretion onto planets varies is not well understood in detail. Therefore, it is necessary to investigate gap formation and mass accretion processes over a wide range of masses and disk parameters in order to clarify the formation and evolution of super-Jupiter-mass planets.
In this study, we performed a set of two-dimensional hydrodynamic simulation of disk-planet interaction taking into account the effect of mass accretion onto the planet by using FARGO. FARGO is a public code dedicated to solving the advection of rotating gas disk and is widely used in the study of disk-planet interaction. Although a global calculation of the disk is necessary to treat the gap formation, the accretion process to a planet is a near-planet phenomenon, so the accretion process is modeled and incorporated into the calculation. In order to test the validity of the modeling of mass accretion onto the planet used in the code, we first performed calculations with different accretion radii, accretion timescales, and smoothing lengths of the planetary gravity. The results show that for appropriate values of accretion radius and smoothing length, a constant mass accretion ratee consistent with previous high-resolution local simulations can be obtained regardless of the accretion timescale.
Based on this validation, we performed numerical simulations with various planetary masses and disk parameters to investigate the mass accretion rate onto the planet when a non-stationary eccentric gap is formed. We found that the mass accretion rate onto the planet increases once the planetary mass becomes heavier than a certain mass due to the formation of the eccentric gap and an increase of the surface density inside the gap. However, we also found that the mass accretion rate decreases again for heavier planets due to the competing effects of the enhancement of the accretion due to the increase of the surface density and the suppression of the accretion due to the increase of the relative velocity of the gas and the planet. We will compare these results with previous numerical calculations and discuss their implication for the formation and evolution of gas giants, especially super-Jupiter-mass planets.
Disk-planet interactions have been actively studied using numerical fluid dynamics simulations in recent years, and the width and depth of the gap formed by the planet and the mass accretion rate of the planet have been investigated in detail. However, most previous studies have focused on Jupiter-mass or lighter planets. The exoplanets discovered so far are highly diverse, and many planets heavier than Jupiter, so-called super-Jupiter-mass planets, have been discovered. When the planetary mass is several times heavier than that of Jupiter, it is known that the outer edge of the gap becomes unstable and an eccentric gap is formed, which is expected to cause a significant difference in characteristics such as surface density inside the gap. However, how the rate of mass accretion onto planets varies is not well understood in detail. Therefore, it is necessary to investigate gap formation and mass accretion processes over a wide range of masses and disk parameters in order to clarify the formation and evolution of super-Jupiter-mass planets.
In this study, we performed a set of two-dimensional hydrodynamic simulation of disk-planet interaction taking into account the effect of mass accretion onto the planet by using FARGO. FARGO is a public code dedicated to solving the advection of rotating gas disk and is widely used in the study of disk-planet interaction. Although a global calculation of the disk is necessary to treat the gap formation, the accretion process to a planet is a near-planet phenomenon, so the accretion process is modeled and incorporated into the calculation. In order to test the validity of the modeling of mass accretion onto the planet used in the code, we first performed calculations with different accretion radii, accretion timescales, and smoothing lengths of the planetary gravity. The results show that for appropriate values of accretion radius and smoothing length, a constant mass accretion ratee consistent with previous high-resolution local simulations can be obtained regardless of the accretion timescale.
Based on this validation, we performed numerical simulations with various planetary masses and disk parameters to investigate the mass accretion rate onto the planet when a non-stationary eccentric gap is formed. We found that the mass accretion rate onto the planet increases once the planetary mass becomes heavier than a certain mass due to the formation of the eccentric gap and an increase of the surface density inside the gap. However, we also found that the mass accretion rate decreases again for heavier planets due to the competing effects of the enhancement of the accretion due to the increase of the surface density and the suppression of the accretion due to the increase of the relative velocity of the gas and the planet. We will compare these results with previous numerical calculations and discuss their implication for the formation and evolution of gas giants, especially super-Jupiter-mass planets.