There are an estimated 100 billion stars in our galaxy. In any given year, none of them blow up.
But an atypical year is coming very soon if Calvin astronomy professor Larry Molnar’s calculations are correct. Molnar is predicting that a star he is monitoring will explode between 2018 and 2020; a comparable prediction has never been made.
“It’s a one-in-a-million chance that you can predict an explosion,” Molnar said of his bold prognostication. “It’s never been done before.”
The star known as KIC 9832227 came to Molnar’s attention in 2013. He was attending an astronomy conference when astronomer Karen Kinemuchi presented her study of the brightness changes of the star, which concluded with a question: Is it pulsing or is it a binary (two stars orbiting each other)?
Also present at the conference was then-student Daniel Van Noord ’14, Molnar’s research assistant. He took the question as a personal challenge and made some observations of the star with the Calvin observatory.
“He looked at how the color of the star correlated with brightness and determined it was definitely binary,” said Molnar. “In fact, he discovered it was actually a contact binary, in which the two stars share a common atmosphere, like two peanuts sharing a single shell.
“From there Dan figured out the orbital period from Kinemuchi’s data and was surprised to discover that the period was not the same as earlier data showed; it was getting shorter,” Molnar continued.
Based on that discovery, Molnar and Van Noord wanted to explore further, so they continued to monitor the orbital period using the Calvin observatory. “We found the period getting even shorter at a faster rate,” said Molnar. They surmised that they might be seeing the merger of two stars, a process that can culminate in a kind of stellar explosion known as a Red Nova.
“It was really exciting to find something like this,” said Van Noord, who came to Calvin because of his interest in studying variable stars. While here he developed a now-internationally used computer program that discovers binary stars in archived data. “It’s proof that the method of research we use at Calvin works.”
The team also took cues from an article by astronomer Romuald Tylenda, who had studied the observational archives to see how another star (V1309 Scorpii) had behaved before it exploded unexpectedly and produced a red nova in 2008. The pre-explosion record of that star is the “Rosetta stone” that Molnar is using to interpret the new data.
“I remember thinking that if I ever see one [a trajectory] that looks like that, I better pay close attention,” said Molnar.
The Next Step
While the new star seemed to be following Tylenda’s model, other models and explanations had to be eliminated. This next step of research was taken by Calvin student Cara Alexander.
“We had to rule out the possibility of a third star,” said Alexander. “That would have been a pedestrian, boring explanation. I was processing data from two telescopes and obtained images that showed a signature of our star and no sign of a third star. Then we knew we were looking at the right thing.
“It took most of the summer to analyze the data, but it was so exciting. To be a part of this research, I don’t know any other place where I would get an opportunity like that; Calvin is an amazing place.”
Jason Smolinski, a Calvin professor collaborating on the project, said the research will produce results such that astronomers have never had before. “Any time stellar explosions are seen, it’s always after the fact,” he said. “That’s interesting, but you always wonder what was there beforehand? For us to be able to study this type of merger in great detail across the entire spectrum is remarkable,” he said.
Being a Christian astronomer gives you so much more wonder, it gives you so much more appreciation knowing that it was handcrafted–it was made by the hand of God. Cara Alexander '16
And Molnar is convinced Calvin is exactly the right place for a discovery of this magnitude.
“Most big scientific projects are done in enormous groups with thousands of people and billions of dollars,” he said. “This project is just the opposite. It’s been done using a small telescope, with one professor and a few students looking for something that is not likely.
“Nobody has ever predicted a nova explosion before. Why pay someone to do something that almost certainly won’t succeed? It’s a high-risk proposal. But at Calvin it’s only my risk, and I can use my work on interesting, open-ended questions to bring extra excitement into my classroom. Some projects still have an advantage when you don’t have as much time or money.”
“Being at Calvin gives you the freedom to explore,” added Alexander. “At large institutions you often study what you can get grants for instead of what needs to be studied.”
And it makes you more awestruck.