I think alot of people use xenia and star polyps interchangably. Personally i consider the star polyps to have the thin (not featherlike) arms or tentacles with the white center. What you have looks more like what i would call a xenia polyp (do a search for xenia, pulsing xenia, or pom pom xenia). These xenia polyps typically have the flat, featherlike tentacles that your polyps appear to have. I have a LOT of pulsing xenia in my tank, and it grows like crazy under my pc lights. I've made many cuttings from them. They seem to grow a little slow at first as they heal from the cutting, then they can expend all their energy on growing after they have healed.