January 10, 2017
Stellar explosion visible to the naked eye could happen in 2022
Calvin College professor Larry Molnar has made a bold prediction, and if he and his colleagues are right, in the year 2022 people standing on Earth will be able to see two stars collide with the only the naked eye, due to the extreme short-lived brightness of the ensuing explosion.
The stars in question, jointly named KIC 9832227, currently orbit one another and even share a common atmosphere, according to NPR reports. However, the researchers predict that they will ultimately “merge and explode... at which time the star will increase its brightness ten thousand fold becoming one of the brighter stars in the heavens for a time.”
Molnar, who presented his team’s findings last week at a meeting of the American Astronomical Society (AAS) in Texas, began tracking KIC 9832227 in 2013, hoping to learn if it was changing brightness because it was pulsing, or if it was a binary star. Not only did they confirm that it was a binary star, but their observations revealed that its orbital period was slowing down.
That discovery brought to mind research involving another star, V1309 Scorpii, which had also started slowing down before unexpectedly exploding in 2008. That explosion produced what is known as a red nova, and the researchers believe KIC 9832227 will share a similar fate by 2022, give or take a year, as they explained in a press release.
Study marks first time astronomers have predicted a red nova
Molnar and his colleagues don’t make those claims lightly. During the course of their research, they were able to eliminate the presence of a companion star with an orbital period greater than 15 years, another possible explanation for the period change, using spectroscopic observations.
In addition, they were able to determine that the rate of orbital period decrease over the last two years has followed predictions they originally made in 2015 and now exceeds that demonstrated by other contact binaries, according to the authors. The bottom line, Molnar emphasized, “is we really think our merging star hypothesis should be taken seriously right now.”
“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,” he added. For their part, he and his colleagues plan to monitor KIC 9832227 in the full range of wavelengths over the next year using several different ground-based observatories and spacecraft to study the star’s radio, infrared and X-ray emissions.
Even though KIC 9832227 is 1,800 light years from Earth, the predicted explosion would cause it to be nearly as bright in the night sky as Polaris, according to National Geographic . “It will be a very dramatic change in the sky, as anyone can see it,” Molar told the publication. “You won’t need a telescope to tell me in 2023 whether I was wrong or I was right.”
“If Larry’s prediction is correct, his project will demonstrate for the first time that astronomers can catch certain binary stars in the act of dying, and that they can track the last few years of a stellar death spiral up to the point of final, dramatic explosion,” added Matt Walhout, dean for research and scholarship at Calvin College. “If the prediction is correct, then for the first time in history, parents will be able to point to a dark spot in the sky and say, ‘Watch, kids, there’s a star hiding in there, but soon it’s going to light up.’”
Image credit: Lunnan et al., 2016.