Particles only carry their time bin.

src/Makefile.am

src/active.h

src/engine.h

src/gravity/Default/gravity.h

src/gravity/Default/gravity_part.h

src/hydro/Gadget2/hydro.h

src/hydro/Gadget2/hydro_part.h

src/kick.h

src/part.h

src/runner.c

src/space.c

src/timeline.h