Very novice astronomer here. I keep seeing terms like "S-Complex" thrown around when talking about asteroids, but no matter how much Googling I do I can't figure out what that exactly means (every article just writes about it assuming the reader knows the definition).
Finally I looked up a free textbook and read the section on asteroids. In Composition and Classification it talks about there being three "types" of asteroids (another term I have seen thrown around): C-type, S-type, and M-type. (I've also seen them referred to as Type C, Type S, etc.)
So are the words "type" and "complex" just synonymous words to classify asteroids? If not, what does "_ -Complex" mean when talking about things like S-Complex asteroids?