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all extremely massive stars lose large amounts of mass to solar wind. I think what they figured out first was the stars with that emission spectrum were still very large and not dwarfs (which is what they would be after creating a nebula)

The mass lost due to solar wind seems extremely large atleast in pictures to the point where it's forming their own nebulae.

I must have misread your first one, it isn't a planetary nebula but it is a form of nebula