... Be Stars . ... Stellar Winds . ... He had found the first emission line star. ... More emission line stars were found soon, and one had to make subclasses to keep some overview. Cas is a main sequence B-type star, and together with other such stars showing hydrogen emission it forms the class of "Be stars", where the "e" stands for emission. ... Struve further speculated that those stars would be surrounded by a disk, basically thrown off the stellar surface by the rapid rotation. ...