I missed it at first as well. The second paragraph implies they are red giants. However, there is a distinction between a red giant and a red super-giant, if that is what you mean.
The "peculiar" puffing behavior of these stars has never been seen before in such red giants, astrophysicist Philip Lucas told AFP.
So, in my typical nature, I went right to the source and shot off an email to Professor Philip Lucas from the University of Hertfordshire. He was one of the primary researchers for the original paper. (P.W. Lucas et al.)
If he responds, I'll post it here.