I'm investigating this sort of thing.
So far I'm not seeing any great variation in selling prices but there
are some oddities.
This picture shows the exploration return value in credits (y axis) for detailed scanning of some low mass (x axis) brown and main sequence dwarf stars.
(I hope you'll all call these
Orlov diagrams.)
There is a very slight variation with the mass of the star (from around 1200 at low mass to 1220 credits at highest mass here.)
Note that there are a bunch of stars which returned only around 1000 credits, and one star which returned over 1400.
I can't tell whether this is down to a bug (either not counting the initial non-detailed scan, or counting it twice) or whether it's something to do with other explorers.
I haven't been able to fit the variation with mass to a nice simple function e.g. BASE VALUE + (ADDITIONAL VALUE * (MASS ^ EXPONENT)).