Exploding Binary Stars Will Light up the Sky in 2022


Five years from now, one of the night sky’s most visible constellations, Cygnus the swan, could get a new addition—the result of a distant star system exploding. And for a time, the event will generate one of the brightest points in the night sky. Located about 1,800 light-years away, the star system KIC 9832227 has long been a focus of study.

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The pair of glittery specks in this binary star system have been circling around each one another for years but it wasn’t till recently that scientists even realized the single flickering spot represented two stars, Nadia Drake reports for National Geographic. The duo have been moving ever closer to one another, and researchers believe they will soon merge in an explosive event known as a nova.

While novae are pretty hard to predict, this instance is one of the first times that astronomers have felt confident enough that their subjects will collide in the near future to put out a statement, Daniel Clery reports for Science magazine.

Professor Lawrence Molnar of the Calvin College’s Dept. of Physics and Astronomy. He predicts KIC 9832227 will collide and explode in 2022.
“We get a predicted explosion date of 2022, give or take a year,” Larry Molnar, an astronomer at Calvin College, said during a presentation at the American Astronomical Society, Drake reports. “It will be a very dramatic change in the sky, as anyone can see it. You won’t need a telescope to tell me in 2023 whether I was wrong or I was right.”

The merging of stars, Drake reports, will make them 10,000 times brighter than they are now. When Molnar and his colleagues first started studying the star system in 2013, all they knew was that it flickered—it was unclear whether it was a pulsing star, or a spinning set of binary stars. The closer they looked, however, the more apparent it became that KIC 9832227 was made up of two stars that are so close to each other that they share an atmosphere, Clery reports. The noticeable flickering came from the fact that the stars are aligned in such a way that they periodically eclipse each other in relation to the Earth, dimming and brightening as they spin.

Diagram showing the summer constellations of Cygnus and Lyra and the position of KIC 9832227 (shown with a red circle).

In the years since, Molnar has become confident enough in his team’s findings that he predicted the two stars would merge and go nova sometime around 2022. While this kind of prediction has never been made before, he says the data gathered from studying the star extremely close to another binary system that went nova in 2008, Deborah Byrd reports for EarthSky.

“Bottom line is we really think our merging star hypothesis should be taken seriously right now and we should be using the next few years to study this intensely so that if it does blow up we will know what led to that explosion,” Molnar said in his presentation, Byrd reports.
 
The model Prof. Molnar and his team constructed of the double star system KIC 9832227, which is a contact binary (i.e. two stars that are touching).

If Molnar is correct, the merger of these two low-density stars should create something called a “red nova” that will put on a fiery show visible even without the use of a telescope. For those looking to catch a glimpse of the nova, the new star could be as bright as Polaris, the North Star, and will appear in the northern wing of Cygnus, Drake reports. Once it explodes, the nova should be visible for most of the year.

“The topic is intriguing … we all have a morbid fascination in finding out the time of death,” Caltech astronomer Shri Kulkarni tells Drake. “It is not a secure result, but not implausible either.”

Even if the stars don’t explode, Molnar hopes that this star system will shed light on the life cycles of stars. And if he’s right, stargazers will have a new phenomenon to watch for months to come.

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