John Wenz explains in his article “Two stars will merge in 2022 and explode into red fury” that come the year 2022, two stars are predicted to merge in a gaseous explosion termed “red nova”. The magnitude of this occurrence will be 2, which will make this explosion as bright as Polaris in the sky. This collision will be visible for up to six months.
This is the first time a nova has ever been predicted. “Lawrence Molnar, a professor of astronomy and physics at Calvin College, was able to find a pair of oddly behaving stars giving an indication of what might happen.”
The objects, currently termed KIC 9832227, are contact binaries. This means that they are so close they are currently touching. This was first discovered by Kepler. Since both stars are low in mass and temperature, it is clear the outcome will show in red. This is why Molnar has termed it the “red nova”.
The reason Molnar is able to predict that this will happen is because he and his team have an example to look at, V1309 Scorpii. This merger was first observed in 2008. Astronomers were able to watch the light curves as the events unfolded and after the booming light show. They used recovery data to trace back the evolution from 2001 on. This allowed them to view the big picture of the decade of progression of the event.
They knew V1309 was a merging star because it was brightening before the explosion. Molnar explains that it isn’t doing so today. “That’s the smoking gun of a merging star”.
Using Kepler data, Molnar found that KIC 9832227 fit the light curve of V1309 almost perfectly. All the radial velocity measurements seemed to indicate a contact binary. By aligning the light curve to the period of time, Molnar and his team were able to predict that the merger would complete in 2022.