Nowhere can I find the etymology of "aan" ( from the verb "aanaa" - to come ) in combinations like " aan pahuNcnaa", "aan paRnaa", "aan khaRaa honaa" etc.
Judging by the "Oxford Hindi-English Dictionary" ( आन abs. poet. and U. = आ, आकर ) in modern prose Hindi, this "aan" is already outdated.
A...