Word for the study of something niche, unique, weird, outdated, lonely

A bit of a broad question but I have an image in my head of a very old guy locked away from society working on something no one else cares about, it could be because it's archaic or because it's so specific to his own obsessions. One would say "Mr Prof has been engaged in a very ______ study for the past hundred years".

I feel like the word is based on a historical figure name? I.e. a Herculean task, the Socratic Method, etc. It's a word like that? I thought it was "Ascetic" at first but that's not it at all.

You're quite close :) The word you're looking for is esoteric, meaning

of special, rare, or unusual interest

and

requiring or exhibiting knowledge that is restricted to a small group

The word is not based on the name of a historical figure, but comes from the Greek word esōterikós, "belonging to an inner circle".