Or, in other words, is it possible to know a star's luminosity in a certain photometric band?
Proxima Centauri's Wikipedia page provides the apparent magntiude in each UBVRIJHK band (getting progressively brighter) as well as the bolometric luminosity and the luminosity in visual wavelengths.
But this amount of information seems limited to Proxima Centauri and a few select other stars.
Is there a way to calculate a star's apparent magnitude/luminosity in another photometric band knowing its visual apparent magnitude/luminosity? Other factors like distance, size, and mass are also known.