Where’s the Flux?

by Natalie Selzer CdeP 2008
Monitoring the most mysterious star in the galaxy at the Thacher Observatory.
Approximately 1,280 light years from Earth, in a stretch of sky marked by the imagined lines of the Cygnus constellation, there’s a highly unusual star that’s making headlines here on our home planet. KIC 8462852—more commonly known by the nickname “Tabby’s Star” in honor of Dr. Tabetha Boyajian, the astronomer and astrophysicist who first reported strange observations associated with it—has displayed erratic and apparently inexplicable changes in starlight brightness, or flux. These variations in flux, measured over a given period of time, make up what is known by astronomers as a star’s light curve; the light curve of Tabby’s Star is so bizarre, and so unlike any other the scientific community has seen before, that Dr. Boyajian has called it “the most mysterious star in our galaxy.” Now, she’s on a mission to unravel the mystery. And thanks to major upgrades that were implemented at the Thacher Observatory in the fall and the spirit of curiosity fostered among students in the revitalized astronomy program, Thacher will be a part of that process.
Thacher’s connection to Tabby’s Star began in December 2016, when a group of about 20 students heard Dr. Boyajian speak in Santa Barbara. She was in the area to launch a new round of Tabby’s Star observations at the Las Cumbres Observatory (LCO), an initiative she’d funded through a successful Kickstarter campaign. The available light curve for KIC 8462852—which she and a host of both professional and citizen scientists alike had been analyzing for years, with no resolution—was collected during the four-year NASA Kepler Mission. During that time, the Kepler spacecraft monitored around 150,000 stars (including Tabby’s) in a single region of the Milky Way, providing ultra-precise light curves for use by the scientific community. But the mission had ended in May 2013. Nobody had been watching Tabby’s Star since then. If Dr. Boyajian wanted to understand KIC 8462852, that needed to change.

“It was a great talk. Everyone was really excited,” remembers Dr. Jon Swift, the director of the Thacher Observatory and a math, physics, and astronomy teacher who had organized the trip. “For one student, in particular, Nick Edwards ’18, the light bulb went on. He told me, ‘We should help monitor Tabby’s Star at Thacher. And I want to be the one to do it.’ So he got an independent in the spring to implement this ongoing survey of Tabby’s Star.”

“When I heard that a student from Thacher wanted to help monitor KIC 8462852, I thought then the same thing that I think now—what a great opportunity for a student to be able to contribute to science!” said Dr. Boyajian, formerly a postdoctoral fellow at Yale and now an assistant professor of physics and astronomy at Louisiana State University. “This star was actually originally discovered by citizen scientists through the website planethunters.org. The planet hunter volunteers come from all backgrounds and all ages, so we’ve encouraged these sorts of collaborations from the start.”

“I found her work so interesting,” said Nick. “She’s at the cutting edge of her field.”

In the spring, Nick got to work. He’d be joining eighteen other professional telescopes in eight sites around the world—all part of the Las Cumbres Observatory network spanning Hawaii, California, Texas, Chile, Israel, South Africa, the Canary Islands, the UK, Tibet, and Australia—to help provide continuous observation of KIC 8462852. But first, he had to get up to speed and prepare the Observatory for the project—no easy feat. Thanks to the fundraising completed during the leadership phase of the capital campaign, the Observatory had the professional research capabilities needed for such a project (installation of a fully robotic dome, a Plane Wave CDK 700 telescope, and an Andor iKon L-Series CCD camera were completed in December). Now, it was just a matter of understanding and implementing the processes needed to conduct the measurements.

“The most challenging part of my independent was that Dr. Swift let me work on my own for the majority of the project,” said Nick. “He was there when I needed help with some math or how to solve a higher-concept problem I was having, but he let me implement those solutions on my own.”

“Nick was learning some really high-level skills that are not traditionally academic,” explained Dr. Swift. “I think a critical skill that he was exercising is this idea that you’re digging into something very specific but at the same time holding in your mind the big picture of where you’re going with that result. That’s an important life skill that is not typically taught at the high school level.”

“There were also some pretty hairy equations that Nick was working with,” Dr. Swift added. “Even some calculus, which he hasn’t studied yet. He was dealing with some really intricate mathematics that were essential for him to interpret the results he was getting. So he learned some new math, but the more important thing, in my mind, was that he was building a new relationship to mathematics and understanding the relevance of things at a totally different level.”

Indeed, it’s here that Dr. Swift zeroes in on the bigger-picture possibilities that have emerged with the revival of the Observatory: the skills, tools, and learnings that extend beyond facts, figures, and hard concepts to prepare students for a whole host of applied learning and real-life pursuits—things that teach kids new and various ways of thinking and problem-solving.

“I’ve been pleasantly surprised by just how much enthusiasm the kids have for the Observatory and the research program, how quickly they’re getting up to speed with some really difficult material, and how willing they are to dive into problems for which there are no answers in the back of a textbook,” said Dr. Chris Vyhnal, chair of the science department and one of the individuals who first imagined a revamped astronomy program and facility. “They’re learning to be self-starters—asking and answering their own questions through innate curiosity, smarts, and hard work. The computer coding they’re doing, the math and physics and astronomy they’re learning—and how mature and responsible and engaged they are with it all—it’s humbling, frankly.”

Dr. Boyajian echoes some of these ideas when asked what she thinks students can learn from real-life projects like this. “Students get firsthand experience in critical thinking and the process of how science works,” she says. “There is never just an experiment one day and then things are done. Science takes time. Often, the experiment shows that the data are not compatible with the theory. So the theory is then revised and another experiment is performed to test the new theory. It’s invaluable for the students to learn how this process works.”

For Nick’s part, he, along with a host of other collaborators, is compiling the data that will ultimately help prove or disprove various theories about what’s causing the extreme “dimming events” in the light curve of Tabby’s Star—something that can often be explained by a planet or other materials orbiting the star and temporarily blocking our view but that, in this case, does not really match the available measurements. In May, just as his spring independent was nearing its close, the data started yielding some very interesting results.

When Nick and Dr. Swift returned from spring Extra-Day Trips, KIC 8462852’s light curve showed another dimming event—the very first observed since the Kepler Mission ended four years ago. They’d missed the very beginning of the “dip” in brightness—the system, for now, cannot yet be automated for more than a couple of days at a time—but had caught most of it, meaning they provided data that could be compared with and used to corroborate measurements from other telescopes that captured the same fluctuation. Articles came out. Theories seemed less likely, or gained credibility. Dr. Boyajian and her hundred or so collaborators moved slightly closer to cracking a cosmic mystery, one that could have repercussions well beyond Tabby’s Star.

This summer, Nick has been keeping tabs on what the Tabby’s Star collaborators are working on via the collaboration tool Slack, which they use to communicate and share information remotely. He or another student will continue to monitor the star from the Thacher Observatory next term, and probably for many terms after that. Nick admits that his work on the project helped him realize that becoming a professional astronomer probably isn’t in the cards for him, though it was an incredibly interesting and satisfying project to work on for a while. In fact, he feels that this realization in and of itself is a productive one. And that’s just fine with Dr. Swift.

“What I’m not doing with this program is creating astronomers,” he is quick to say. “Once they build up confidence and fluency in mathematics, programming, data, quantitative endeavors, then it’s transferable to anything. They can go into whatever field they like and they’re going to have this really wonderful, rock-solid foundation to work from.”

This piece originally appeared in the summer 2017 issue of Thacher magazine.

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