star colors

I haven't played this game in a while, and I recently got the new expansion.  For some reason I thought that only the yellow color stars had habitable planets, except for the puprple ones sometimes had really good ones.  But I was playing last night and I noticed some habitable planets around an orange star.  I completely missed them because I wasn't looking for them around an orange star.  Has this been changed, or am I just remembering this wrong?

Thank you.