There’s something not right about KIC 8462852.
This star in the Cygnus constellation is not following the rules of other known stars or even the laws astronomers see governing the other celestial bodies in the sky.
It’s a mystery.
Discovered by citizen scientists and then analyzed by now-LSU astronomer Tabetha Boyajian, this “Tabby’s Star,” is dimming over the long term while at the same time experiencing random dips in brightness.
“They don’t do that,” said Bradley Schaefer, professor of physics and astronomy at LSU who has done work on these strange occurrences. “This star is just an ordinary, average star out in the middle of nowhere.”
About a year ago, Boyajian published a paper showing that the star’s brightness dimmed by 20 percent for about a day, and then got brighter again. The paper created quite a stir.
“I was dumbfounded and had never seen anything like this,” Schaefer said. The star is a little more massive than the sun, but in every way it’s pretty ordinary, he said. “Stars at the age of that star, nothing is changing in them.”
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So with the new findings, scientists started to run through the possibilities. Maybe it’s a planet or other body passing through our line of sight, but the pattern of the dips in brightness aren’t regular like you would get with an orbit. Maybe gas or dust clouds were causing the star to appear to dim over time. But no evidence was found on either possibility.
Schaefer looked at a longer-term period of time as seen through archival photo plates from Harvard that showed the star’s brightness. What he found is not only are there these quick dips, but the star has been dimming over time – about 20 percent between 1890 and 1989. Later reports have looked at different time periods, and the same long-term dimming, along with sudden dips, can be found over days, weeks, months, years, decades and centuries.
“It’s changing up and down on all kinds of time scales,” Schaefer said.
For astronomers, it’s like walking along the road and seeing a rock suddenly turn from brown to red and then back to brown a few minutes later. Nothing in your experience, or what is known in science, would provide an explanation for why that happened, Schaefer said.
In the same way, a star of this type can’t be doing what it’s doing.
“It might be the tip of the iceberg of some wacko new theory no one has thought of before,” Schaefer said. Or, he said, it could be something that is explained by some new discovery.
Boyajian decided to try to capture the next “dip” in brightness and run a spectrum study on the star to try to determine if dust, gas or another cosmic body could account for the changes.
However, getting dedicated telescope time is expensive, so Boyajian turned to the type of crowdsourcing that helped finance the discovery of the star’s strange ways in the first place: Boyajian set up a Kickstarter campaign.
About 1,700 people pledged more than $107,000, which should be enough to pay for a year and a half of telescope time.
“This is a whole new mode for funding science,” Schaefer said. It fits within the ways regular people around the world are helping discover new things in space through groups like Planet Hunters or SETI at Home by combing through information and reporting back to science groups. It’s something he, his family and even his mom participate in, from looking for new planets to trying to find signals from space.
“My mom is out there looking for alien life-forms,” he said, referring to the SETI at Home program. “If my mom can do it, you can do it.”