It’s been called Kepler’s “Alien Megastructure” star, and it continues to befuddle scientists. Now, a new study indicates that KIC 8462852 has been dimming at a massive rate, causing scientists to scratch their heads as to what could be causing it.

Months ago, rumors circulated about the stars periodic dimming, with some even suggesting that perhaps there was some alien megastructure around the star to harvest its energy. Further observations suggested that it was more likely orbiting bodies like comets that were causing this dimming, but now scientists find that the signals are diminishing — a confusing discovery.

Astronomers Ben Montet of the California Institute of Technology (Caltech) and Joshua Simon of the Carnegie Institution published a study that looks into the phenomenon that is “Tabby’s Star.”

They found that the luminosity of the star dipped by 20 percent, and there seems to be a clear downward trend during its observational period — with a bizarre sudden drop in recent months. Tabby’s Star dimmed about 0.34 percent every year for the first few years it was observed, but in the next 200 days it has plunged 2.5 percent. There has been no other star in the vicinity observed with such a drop in brightness.

“We examine whether the rapid decline could be caused by a cloud of transiting circumstellar material, finding while such a cloud could evade detection in sub-mm observations, the transit ingress and duration cannot be explained by a simple cloud model,” the abstract states. “Moreover, this model cannot account for the observed longer-term dimming. No known or proposed stellar phenomena can fully explain all aspects of the observed light curve.”