MassTaper
This parameter indicates the
timescale over which the planet masses are "turned on" for the
potential evaluation at the begining of a simulation, in orbital
timescales at r=1. The
tapering function is the one of the EU
Test Comparison problem. Note
that the tapering is just applied at the potential evaluation, and not
through the full hydro timestep. In particular the torque values output
during the mass tapering should not be trusted. This parameter defaults
to 0 (full planet masses applied straight away).