What’s the best way to estimate dust extinction for nearby stars?

It is one of the sad realities of astronomy, for observers like myself, that when you look at any star or galaxy, you cannot assume there is nothing in the way. Interstellar dust and gas is a real problem, typically getting worse the further away your object is, or if you’re looking along a particularly dusty line-of-sight. It typically absorbs (extinguishes) bluer light, leaving your star looking redder than it should (hence, “reddening”).

There are a number of ways to estimate and account for reddening. One of the most common is using a dust map, but there are also empirical methods that relate reddening to the strength of the sodium D lines. For nearby stars where we have high-resolution spectroscopy, like the ones I work on, it’s preferable to use the empirical methods, but these need some improvements. I’m currently working on a few proof-of-concept research ideas to create some new and improved empirical relations, calibrated using observations of Galactic rather than extra-Galactic objects.