Honestly, it could have different meanings depending on the context. It might signify that the stories are new, featured, or have some specific attribute assigned to them.
I don't have a definite answer for you. Sometimes, a green circle around stories could be a visual cue for priority, popularity, or a particular classification set by the platform or website. But it's hard to say for sure without more information.
I'm not sure. Maybe it indicates some sort of special status or category for the stories.