Students digging into data archive spot mysterious X-ray source

Another possibility is that the source is a so-called chromospherically active binary, a dual system of stars with intense X-ray activity caused by processes in their chromosphere, an intermediate layer in a star’s atmosphere. But even in this case, it does not closely match the properties of any known object of this class.

Interesting. I guess an alien source was ruled out due to magnitude of the source. Still, would be interesting to see if there is potentially an underlying communication pattern there.