Formation of planetary systems by pebble accretion and migration: Growth of gas giants. (arXiv:1902.08771v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bitsch_B/0/1/0/all/0/1">Bertram Bitsch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Izidoro_A/0/1/0/all/0/1">André Izidoro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johansen_A/0/1/0/all/0/1">Anders Johansen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Raymond_S/0/1/0/all/0/1">Sean N. Raymond</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Morbidelli_A/0/1/0/all/0/1">Alessandro Morbidelli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lambrechts_M/0/1/0/all/0/1">Michiel Lambrechts</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jacobson_S/0/1/0/all/0/1">Seth A. Jacobson</a>
Giant planets migrate though the protoplanetary disc as they grow. We
investigate how the formation of planetary systems depends on the radial flux
of pebbles through the protoplanetary disc and on the planet migration rate.
Our N-body simulations confirm previous findings that Jupiter-like planets in
orbits outside the water ice line originate from embryos starting out at 20-40
AU when using nominal type-I and type-II migration rates and a pebble flux of
100-200 Earth masses per million years, enough to grow Jupiter within the
lifetime of the solar nebula. The planetary embryos placed up to 30AU migrate
into the inner system (r<1AU) and form super-Earths or hot and warm gas giants,
producing systems that are inconsistent with the configuration of the solar
system, but consistent with some exoplanetary systems. We also explore slower
migration rates which allow the formation of gas giants from embryos
originating from the 5-10AU region, which are stranded exterior to 1 AU at the
end of the gas-disc phase. We identify a pebble flux threshold below which
migration dominates and moves the planetary core to the inner disc, where the
pebble isolation mass is too low for the planet to accrete gas efficiently.
Giant planet growth requires a sufficiently-high pebble flux to enable growth
to out-compete migration. Even higher pebble fluxes produce systems with
multiple gas giants. We show that planetary embryos starting interior to 5AU do
not grow into gas giants, even if migration is slow and the pebble flux is
large. Instead they grow to the mass regime of super-Earths. This stunted
growth is caused by the low pebble isolation mass in the inner disc and is
independent of the pebble flux. Additionally we show that the long term
evolution of our formed planetary systems can produce systems with hot
super-Earths and outer gas giants as well as systems of giants on eccentric
orbits (abridged).
Giant planets migrate though the protoplanetary disc as they grow. We
investigate how the formation of planetary systems depends on the radial flux
of pebbles through the protoplanetary disc and on the planet migration rate.
Our N-body simulations confirm previous findings that Jupiter-like planets in
orbits outside the water ice line originate from embryos starting out at 20-40
AU when using nominal type-I and type-II migration rates and a pebble flux of
100-200 Earth masses per million years, enough to grow Jupiter within the
lifetime of the solar nebula. The planetary embryos placed up to 30AU migrate
into the inner system (r<1AU) and form super-Earths or hot and warm gas giants,
producing systems that are inconsistent with the configuration of the solar
system, but consistent with some exoplanetary systems. We also explore slower
migration rates which allow the formation of gas giants from embryos
originating from the 5-10AU region, which are stranded exterior to 1 AU at the
end of the gas-disc phase. We identify a pebble flux threshold below which
migration dominates and moves the planetary core to the inner disc, where the
pebble isolation mass is too low for the planet to accrete gas efficiently.
Giant planet growth requires a sufficiently-high pebble flux to enable growth
to out-compete migration. Even higher pebble fluxes produce systems with
multiple gas giants. We show that planetary embryos starting interior to 5AU do
not grow into gas giants, even if migration is slow and the pebble flux is
large. Instead they grow to the mass regime of super-Earths. This stunted
growth is caused by the low pebble isolation mass in the inner disc and is
independent of the pebble flux. Additionally we show that the long term
evolution of our formed planetary systems can produce systems with hot
super-Earths and outer gas giants as well as systems of giants on eccentric
orbits (abridged).
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