We’re not saying it’s aliens, but I also can’t tell you it’s definitely not aliens.
Late last week, astronomers around the world prepared to work through the weekend observing one of the most enigmatic stars known to humanity: KIC 8462852, better known as Tabby’s Star, Boyajian’s Star or the “alien megastructures star.” Amateur and pro star watchers trained telescopes on the star some 1,400 light-years away, and now we’re able to get an early look at those observations and take a few tiny, tentative steps toward solving the mystery of this very weird star.
The alert went out on Friday that the odd dips in the brightness of the star first discovered in Kepler data via a crowdsourced effort were happening once again — these dips have yet to be explained, giving rise to all sorts of theories, including far-out ideas like huge megastructures built by an advanced alien civilization. Astrophysicist Tabetha Boyajian, who led the citizen science project and for whom the star is named, predicted last year that the star’s brightness might dip again as soon as May 2017.
When her prediction began to come true last week, she notified major observatories and amateur astronomy groups via social media and other channels, and many swung their lenses in the direction of the constellation Cygnus and the mysterious star.
By Sunday, we were beginning to learn more about the latest “dimming event” going on with KIC 8462852.
What makes this star so bizarre is that its dips in brightness don’t seem to follow any obvious patterns. When planets or even comets pass in front of their stars, it tends to happen at regular, predictable intervals and they usually block out the same amount of a star’s light as the last time they made a pass. But the dips seen in the brightness of KIC 8462852 don’t occur on a very tight schedule and they vary in how much they dim the star’s light: anywhere from three to more than 20 percent.
To make things even weirder, old observations of the star show it has also dimmed slowly over the course of the past century. So in addition to these odd short term dips where something seems to pass in front of the star, it’s also getting noticeably less bright over the long term, as if someone is turning down its energy output like you might with your living room lights using a dimmer switch. We just don’t see many, if any, other stars behaving this way.
So back to the latest observations: by May 19, the light seen from KIC 8462853 had dropped by as much as 3 percent over a period of around 24 hours. This according to new data from the Las Cumbres Observatory in California that Boyajian discussed with fellow scientist David Kipping from Columbia University in the below livestream recorded Sunday.
By Monday morning, astronomer Jason Wright (who was the first to put forward the idea that alien megastuctures could explain the unpredictable dips) noted that the dip seemed to be over and the star was returning to its normal brightness.
As it turns out, the dip seen over the weekend is roughly similar to a 3 percent dip observed by the Kepler Space Telescope a few years back, leading Boyajian and others to wonder if it might repeat or follow some other sort of pattern after all.
“We’re still quite unsure if it is in fact a duplicate of that event, meaning that it’s the same object that’s passing in front of (the star). It could be a different object or even the same object that’s (rotated) to have a different contrast or signature against the star,” she explains.
The new observations will be analyzed more rigorously over the coming days and weeks and hopefully provide some new insights into the mystery of the star. In fact, if the weird dips in brightness do follow a pattern, this could be just the beginning of the latest round of them.
As Wright points out in the tweeted graph below, if this is a repeat of previous dips, then more action from Boyajian’s Star is just around the corner. The black line on the graph shows Kepler data from previous dips overlaid on the multicolor data from multiple telescopes showing last week’s dip. Note that if we’re seeing a repeating pattern, more and deeper dips could happen this week.
If that happens, then we could really begin to get to the bottom of the mystery. But for now, the new observations already provide some very interesting food for thought. If the dip seen last week is actually the shadow of something passing in front of the star on a regular basis, it’s something pretty massive. In fact, Kipping estimates it would be about five times the radius of our own sun and bigger than KIC 8462853 itself.
And while the odds that whatever is getting in between the star and our telescopes is artificial are still very low, that possibility still can’t be ruled out. What’s more, Boyajian herself (who has always been hesitant to fan the hungry flame of the alien megastructures hypothesis) notes that it appears the large object blocking the star’s light could even be within the habitable zone of the solar system.
“I think it’s an interesting coincidence,” she says. “You can imagine some Death Star blowing up a planet that was inhabited perhaps and this is the pieces of shrapnel from the planet that is orbiting around the star and blocking the light.
You can imagine it, but the data doesn’t quite fit the alien hypothesis perfectly. A more likely explanation might be a huge cloud of dust, perhaps from some big time colliding comets or even planets, but who knows at this point.
Boyajian, for one, says she’s keeping an open mind about what could be causing the weird observations of the star that now carries her name.
Meanwhile, telescopes around the world will continue to keep a close eye on this very weird star, including the SETI Institute’s Allen Telescope Array, which continues to listen for signs of intelligent life from Boyajian’s star. So far, any aliens that might be building a massive Dyson sphere around the star seem to be doing their work with their radios turned off, because SETI researchers have yet to pick up signs of life from the star.
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