The migration of gas giant planets in gravitationally unstable discs
  Planets form in the discs of gas and dust that surround young stars. It is
not known whether gas giant planets on wide orbits form the same way as Jupiter
or by fragmentation of gravitationally unstable discs. Here we show that a
giant planet, which has formed in the outer regions of a protostellar disc,
initially migrates fast towards the central star (migration timescale ~10,000
yr) while accreting gas from the disc. However, in contrast with previous
studies, we find that the planet eventually opens up a gap in the disc and the
migration is essentially halted. At the same time, accretion-powered radiative
feedback from the planet, significantly limits its mass growth, keeping it
within the planetary mass regime (i.e. below the deuterium burning limit) at
least for the initial stages of disc evolution. Giant planets may therefore be
able to survive on wide orbits despite their initial fast inward migration,
shaping the environment in which terrestrial planets that may harbour life
form.
