I know - Wiki should have been my first stop.
But digging through a H-R Diagram is such a puzzle for me I was hoping a science chatterbox would lay it all out in a couple of simple sentences.
Learned several cool new things, though, which you may already know.....
Red dwarfs convect helium throughout the star, thus there is no helium ash build up in the core.
The smallest red dwarfs can theoretically burn for more than a trillion years.
Alpha Centauri B is an orange dwarf.