1 research outputs found
Satellites Form Fast & Late: a Population Synthesis for the Galilean Moons
The satellites of Jupiter are thought to form in a circumplanetary disc. Here
we address their formation and orbital evolution with a population synthesis
approach, by varying the dust-to-gas ratio, the disc dispersal timescale and
the dust refilling timescale. The circumplanetary disc initial conditions
(density and temperature) are directly drawn from the results of 3D radiative
hydrodynamical simulations. The disc evolution is taken into account within the
population synthesis. The satellitesimals were assumed to grow via streaming
instability. We find that the moons form fast, often within years, due
to the short orbital timescales in the circumplanetary disc. They form in
sequence, and many are lost into the planet due to fast type I migration,
polluting Jupiter's envelope with typically 15 Earth-masses of metals. The last
generation of moons can form very late in the evolution of the giant planet,
when the disc has already lost more than the 99% of its mass. The late
circumplanetary disc is cold enough to sustain water ice, hence not
surprisingly the 85% of the moon population has icy composition. The
distribution of the satellite-masses is peaking slightly above Galilean masses,
up until a few Earth-masses, in a regime which is observable with the current
instrumentation around Jupiter-analog exoplanets orbiting sufficiently close to
their host stars. We also find that systems with Galilean-like masses occur in
20% of the cases and they are more likely when discs have long dispersion
timescales and high dust-to-gas ratios.Comment: 15 pages, 17 figures. Accepted by MNRAS, please check the final
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