Remember that star that caused all the fuss about alien megastructures last year? The more astronomers look at it, the weirder it seems to get. New research neither confirms nor denies that intelligent life is behind the behavior of the strangest star in the universe, but deepens in the mystery.

It turns out that the star, officially called KIC 8462852 but also known as Tabby’s Star, is behaving strangely in not just one but three different ways, according to Carnegie Science.

“This star was already completely unique because of its sporadic dimming episodes,” says Josh Simon of Carnegie Science in the news release. “But now we see that it has other features that are just as strange, both slowly dimming for almost three years and then suddenly getting fainter much more rapidly.”

Tabby’s Star is located in the Cygnus constellation, about 1,500 light years from Earth. It caused a stir when stargazers noticed that it would sometimes dim at irregular intervals, by as much as 22 percent. It would take 22 planets the size of Jupiter to block that much light, which led to the wildly improbable speculation that an alien civilization had built some sort of superstructure that was sometimes blocking the light.

Since then, different teams of astronomers and alien-hunters have worked to confirm or deny the theory, with not much luck. Although no one has been able to perfectly explain the strange light patterns through the known laws of the physical universe, efforts to prove extraterrestrials are involved have come up dry too.

Brightness of KIC 8462852 as a function of time. The solid line represents the authors' best estimate of the brightness of the star during the Kepler mission, while the shaded region represents the uncertainty on the brightness at any time. The authors find the star’s brightness slowly decreased over time until early 2012, when it rapidly dimmed in brightness by 2 percent over six months. Image is courtesy of Ben Montet.
Tabby's Star dimmed slowly, and then very quickly, between 2009 and 2013.

This new effort, led by Simon with Ben Montet of Caltech, analyzed four years of data from NASA’s Kepler space telescope in hopes of uncovering the star’s secrets. They found, in addition to the strange dimming events, Tabby’s Star gradually dimmed over the first three years of data, and then dimmed much more quickly over a six-month period after that.

The researchers compared this data to that for 500 similar stars, and found that very few showed this gradual dimming pattern, and none dimmed as rapidly, or as much overall. Taken together, these light patterns shown by Tabby’s Star are astonishing.

“It’s a big challenge to come up with a good explanation for a star doing three different things that have never been seen before,” says Simon.

As of now, we still have exactly zero proof that Tabby’s Star’s weirdness has anything to do with intelligent extraterrestrial life, and yet we also have zero proof that it doesn’t. Most scientists are erring on the side of betting there’s a natural cause for all this, but until they find it, KIC 8462852 will remain a fabulous mystery.

Photos via Ben Montet/Carnegie Science, NASA/JPL-Caltech