Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dynamics of pebbles in the vicinity of a growing planetary embryo:
  hydro-dynamical simulations   Understanding the growth of the cores of giant planets is a difficult
problem. Recently, Lambrechts and Johansen (2012; 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. Here, 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. 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. 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
LJ12 and tends to their value with increasing pebble-size. We conclude that 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.

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The categories of this paper are: cond-mat
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The categories of this paper are: alg-geom
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The categories of this paper are: cs
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
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The categories of this paper are: physics
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The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
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The categories of this paper are: eess
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: solv-int