When did simulations suggest the close pass by the Sgr Dwarf occurred to provide the nudge for Solar System formation?

Approximately 4.5 billion years ago.

Astrophysical modeling, which integrates the mechanics of the gravitational disruption caused by the Sgr Dwarf with observational data concerning the age of our stellar neighborhood, provides an estimated timeline for the initiating event. Current simulations suggest that one of the critical close passages made by the Sagittarius Dwarf Galaxy through the Milky Way plane occurred around 4.5 billion years ago. This timeframe aligns closely with the calculated age of the Sun, estimated to be roughly 4.6 billion years old, indicating that the gravitational 'slap' from the dwarf galaxy provided the exact necessary compression at the precise moment required for the solar nebula to begin its contraction.