Dynamics of pebbles in the vicinity of a growing planetary embryo: hydro-dynamical simulations

By A. Morbidelli, D. Nesvorný. 2012

136 citations recorded by the source corpus.

Context. Understanding the growth of the cores of giant planets is a difficult problem. Recently, Lambrechts & Johansen (2012, A&A, 544, A32, LJ12) proposed a new model in which the cores grow by the accretion of pebble-size objects, as the latter drift towards the star due to gas drag. Aims. We investigate the dynamics of pebble-size objects in the vicinity of planetary embryos of 1 and 5 Earth masses and the resulting accretion rates. Methods. We use hydrodynamical simulations, in which the embryo influences the dynamics of the gas and the pebbles suffer gas drag according to the local gas density and velocities. Results. The pebble dynamics in the vicinity of the planetary embryo is non-trivial, and it changes significantly with the pebble size. Nevertheless, the accretion rate of the embryo that we measure is within an order of magnitude of the rate estimated in LJ 12 and tends to their value with increasing pebble-size. Conclusions. The model by LJ12 has the potential to explain the rapid growth of giant planet cores. The actual accretion rates however, depend on the surface density of pebble size objects in the disk, which is unknown to date.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/ef33a2ea0ca7aa888a4879c5d50c3e751257af1d

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In Astronomy and Astrophysics

Citations in the corpus

The structure of protoplanetary discs around evolving young stars (2014, background): “…by embryos is slower than disc lifetim s (Pollack et al. 1996; Rafikov 2004; Levison et al. 2010), but growth time scales can be drastically reduced by considering the accretion of pebbles (Johansen & Lacerda 2010; Ormel & Klahr 2010; Lambrechts & Johansen 2012; Morbidelli & Nesvorny 2012).”
Fossilized condensation lines in the Solar System protoplanetary disk (2015, methodology): “However, it has been pointed out in Morbidelli and Nesvorny (2012) that when a planet reaches a mass of the order of 50 Earth masses it starts opening a partial gap in the disk.”
Forming the cores of giant planets from the radial pebble flux in protoplanetary discs (2014, background): “However, there exists a pebble isolation mass, a mass where the core perturbs the gas disc and halts pebble accretion abruptly (Morbidelli & Nesvorny 2012).”
The great dichotomy of the Solar System: Small terrestrial embryos and massive giant planet cores (2015, methodology): “…of pebbles inside the orbit of the outer embryo is (1 − F ) times that going towards the orbit of the outer embryo, where F is the filtering factor (Morbidelli and Nesvorny, 2012), namely the fraction of the pebble flux intercepted by the outer embryo, which is computed numerically from the…”
Separating gas-giant and ice-giant planets by halting pebble accretion (2014, methodology): “Previous studies (Johansen & Lacerda 2010; Ormel & Klahr 2010; Bromley & Kenyon 2011; Lambrechts & Johansen 2012; Morbidelli & Nesvorny 2012) demonstrate that this is the result of gas drag operating on pebbles, which dramatically increases the accretion cross section (Sect.”
Pebble-isolation mass: Scaling law and implications for the formation of super-Earths and gas giants (2018, background): “Pebble accretion stops when the gap carved by the planet generates a pressure maximum outside of its orbit, which stops the inward flux of pebbles (Morbidelli & Nesvorny 2012; Lambrechts et al. 2014).”