Editing Planetary migration (section)

==== Type III disk migration ====
<em>Type III disk migration</em> applies to fairly extreme disk / planet cases and is characterized by extremely short migration timescales.<ref name=masset_2003>{{cite journal |author1=Masset, F.S. |author2=Papaloizou, J.C.B. |title=Runaway migration and the formation of hot Jupiters |journal=The Astrophysical Journal |date=2003 |volume=588 |issue=1 |pages=494–508 |doi=10.1086/373892 |arxiv=astro-ph/0301171 |bibcode=2003ApJ...588..494M|s2cid=7483596 }}</ref><ref name=dangelo_2005>{{cite journal |author1=D'Angelo, G. |author2=Bate, M.R.B. |author3=Lubow, S.H. |title=The dependence of protoplanet migration rates on co-orbital torques |journal=Monthly Notices of the Royal Astronomical Society |date=2005 |volume=358 |issue=2 |pages=316–332 |doi=10.1111/j.1365-2966.2005.08866.x |doi-access=free |arxiv=astro-ph/0411705 |bibcode=2005MNRAS.358..316D|s2cid=14640974 }}</ref><ref name="dangelo_lubow_2008"/> Although sometimes referred to as "runaway migration", the migration rate does not necessarily increase over time.<ref name="masset_2003"/><ref name=dangelo_2005 /> '''Type&nbsp;III''' migration is driven by the co-orbital torques from gas trapped in the planet's [[Lagrangian point|libration regions]] and from an initial, relatively fast, planetary radial motion. The planet's radial motion displaces gas in its co-orbital region, creating a density asymmetry between the gas on the leading and the trailing side of the planet.<ref name="dangelo_lubow_2008"/><ref name="li2011"/> Type III migration applies to disks that are relatively massive and to planets that can only open partial gaps in the gas disk.<ref name="li2011"/><ref name="dangelo_lubow_2008"/><ref name="masset_2003"/> Previous interpretations linked Type&nbsp;III migration to gas streaming across the orbit of the planet in the opposite direction as the planet's radial motion, creating a positive feedback loop.<ref name=masset_2003 /> Fast outward migration may also occur temporarily, delivering giant planets to distant orbits, if later Type&nbsp;II migration is ineffective at driving the planets back.<ref name="Pierens_Raymond_2016">{{cite journal |last1=Pierens |first1=A. |last2=Raymond |first2=S.N. |title=Migration of accreting planets in radiative discs from dynamical torques|journal=Monthly Notices of the Royal Astronomical Society |date=2016 |volume=462 |issue=4 |pages=4130–4140 |doi=10.1093/mnras/stw1904 |doi-access=free |arxiv=1608.08756 |bibcode=2016MNRAS.462.4130P|s2cid=119225370 }}</ref>