Migration of pairs of giant planets in low-viscosity discs

Abstract

When considering the migration of Jupiter and Saturn, a classical result is to find the planets migrating outwards and locked in the 3:2 mean motion resonance (MMR). These results were obtained in the framework of viscously accreting discs, in which the observed stellar accretion rates constrained the viscosity values. However, it has recently been shown observationally and theoretically that discs are probably less viscous than previously thought. Therefore, in this paper, we explore the dynamics of pairs of giant planets in low-viscosity discs. We performed two-dimensional hydrodynamical simulations using the grid-based code FARGOCA. In contrast to classical viscous discs, we find that the outer planet never crosses the 2:1 resonance and the pair does not migrate outwards. After a wide parameter exploration, including the mass of the outer planet, we find that the planets are primarily locked in the 2:1 MMR and in some cases in the 5:2 MMR. We explain semi-analytically why it is not possible for the outer planet to cross the 2:1 MMR in a low-viscosity disc. We find that pairs of giant planets migrate inwards in low-viscosity discs. Although, in some cases, having a pair of giant planets can slow down the migration speed with respect to a single planet. Such pairs of slowly migrating planets may be located, at the end of the disc phase, in the population of exoplanets of 'warm Jupiters'. However, the planets never migrate outwards. These results could have strong implications on the Solar System's formation scenarios if the Sun's protoplanetary disc had a low viscosity.

14 pages, 14 figures. Accepted to A&A

References in corpus (19)

• Two accreting protoplanets around the young star PDS 70
• A comparative study of disc-planet interaction
• Dynamics of the giant planets of the solar system in the gaseous proto-planetary disk and relationship to the current orbital architecture
• Close-in planetesimal formation by pile-up of drifting pebbles
• Cavity opening by a giant planet in a protoplanetary disc and effects on planetary migration
• Contemporary formation of early solar system planetesimals at two distinct radial locations
• A highly settled disk around Oph 163131
• The early instability scenario: terrestrial planet formation during the giant planet instability, and the effect of collisional fragmentation
• Constraining the giant planets' initial configuration from their evolution: implications for the timing of the planetary instability
• Outward migration of Jupiter and Saturn in 3:2 or 2:1 resonance in radiative disks: implications for the Grand Tack and Nice models
• The dynamical role of the circumplanetary disc in planetary migration
• Slowly-growing gap-opening planets trigger weaker vortices
• The Role of Early Giant Planet Instability in the Terrestrial Planet Formation
• A dusty origin for the correlation between protoplanetary disc accretion rates and dust masses
• Migration of Jupiter mass planets in low viscosity discs
• The fate of planetesimals formed at planetary gap edges
• Born extra-eccentric: A broad spectrum of primordial configurations of the gas giants that match their present-day orbits
• Capture and migration of Jupiter and Saturn in mean motion resonance in a gaseous protoplanetary disc
• Constraining the masses of planets in protoplanetary discs from the presence or absence of vortices -- Comparison with ALMA observations

Cited by in corpus (1)

• Searching for the Grand Tack in Exoplanetary Data