Contrails, as far as I understand them, are caused by either a pressure change that forces the condensation of H2O(g) OR by the release of warm H2O from a combustion engine. Most plane contrails, I would assume, operate largely by this second mechanism as they burn jet fuel and release warm CO2 and H2O.
My question is, can the first mechanism alone be enough to create a contrail? Would a supersonic object passing through Earth's atmosphere leave behind a contrail? If so, what conditions are required for this - presumably high pressure (close to the surface of the Earth) and high speed?
For those curious, this started out as a question on Worldbuilding and has been asked again here per a wise comment.