Why are star-forming regions in the Large and Small Magellanic Clouds mostly blue in colour?
In general, I think that younger stars tend to be more massive and hotter than older stars. This drives them toward the blue end of the H-R diagram. This is not necessarily a continuous process, i.e. they may not later evolve into red giants – they may just supernova early and disappear, only to show up later as less massive, 2nd or 3rd generation stars. I guess what I am saying is that if you are looking for massive, blue white stars, you need to look in star formation regions – before they supernova and disappear. Since they are so bright, they will also tend to photographically swamp out other smaller stars in the same region.
