Tabetha Boyajian, an assistant professor of Physics and Astronomy at LSU and a new addition to LSU College of Science faculty as of fall 2016, has a star in her name. But Tabby’s Star, or more officially KIC 8462852, isn’t just any old star. It’s been called the most mysterious star in the universe.
It was a group of citizen scientists, via Zooniverse’s Planet Hunters, a web-based citizen science project, who first discovered strange light patterns emanating from KIC 8462852. The Planet Hunters site trains citizen scientists, including people from all walks of life and levels of astronomy knowledge, to read star light curves captured by NASA’s Kepler space observatory. Through the project, anyone can help find undiscovered planets by looking at how the brightness of a star changes over time, where dips in brightness over time can be explained by planets transiting or passing in front of the star as seen from Earth. By monitoring the light curves of KIC 8462852, Planet Hunters volunteers found that the star regularly undergoes a series of odd, sharp dips in brightness. But these dips are so strange, so irregular, that they can’t be explained by a planet transiting the star or any other behavior that stars are known to have.
“The human brain has an amazing ability for pattern recognition, sometimes even better than a computer,” Boyajian said during a TED talk in 2016. Planet Hunters harnesses that ability and enables citizens, scientists and amateurs alike, to contribute to scientific research. The science team behind Planet Hunters has published several papers on planets found through the project that computers have missed.
Boyajian joined the Planet Hunters team in 2012 as a postdoctoral fellow in the exoplanets group at Yale. Soon afterwards she was notified by Planet Hunters users of a very unusual star.
“When Planet Hunters users were classifying the Kepler data, they came across this one star that didn’t fit into any category that they had seen before,” Boyajian said. “So they started talking about it, and talking about it. It took a while for this discussion to reach the Planet Hunters science team. When I first learned about it, I wouldn’t have given it a second thought if it weren’t for some of the experienced Planet Hunters users I know personally convincing me to look at the data more closely. At first, I just thought the data was bad. If it weren’t for citizen scientists, this is something we would have missed.”
One of the most powerful things about citizen science projects, Boyajian said, is that citizens can identify trends or discover things that are really cool that scientists wouldn’t have been looking for. “This was a serendipitous discovery that happened because a group of people was sifting through the dataset. It likely wouldn’t have been found otherwise.”
Boyajian published a paper about KIC 8462852 in 2016, and as a researcher at LSU continues to study this particular star, amongst other stars, in collaboration with various citizen groups and amateur observers. In her 2016 paper, coauthored by researchers at various other institutions and even amateur astronomers, Boyajian concluded that the most likely explanation for the light dips in data from the star was the passage of a family of exocomet or planetesimal fragments, or debris left over from comet collisions. One of the strangest and most unlikely explanations that others have suggested is that an alien megastructure surrounds the star. Brad Schaefer, a professor of in the Department of Physics and Astronomy at LSU, has also published data about Tabby’s Star revealing that the star has been experiencing a strange long-term dimming over time.
To really figure out what’s going on with this star, Boyajian and collaborators need more data.
“We need more information on the color of these dips in light,” Boyajian said. “Kepler only observed this star in one wavelength – it didn’t give any color information. Color information could tell us the composition of the material passing in front of this star. If it’s a cloud of dust, the data signal will have a different shape and depth in the blue range than it does in red. If it’s an opaque object such as a planet, the signal will look different still. So color information will tell us a lot.”
Since the original discovery of the star, Boyajian has been working with amateur observers and astronomers through the American Association of Variable Star Observers (AAVSO) to get more data from individual observations of KIC 8462852, which can be clearly seen using a small telescope. Following an AAVSO alert about this star in October 2015, more than 50 observers around the world have been contributing data to the AAVSO database that Boyajian can use. The observers come from all walks of time, from a former engineer at NASA JPL to an owner of a bike shop in Arizona.
“I’m working with people who just want to contribute to science. It’s amazing,” Boyajian said. “It’s also a brilliant solution, because with 50 people observing all over the world, where if it’s raining at one site it’s clear in another or if it’s daytime at one site it’s nighttime in another, we actually get full coverage in terms of monitoring of the star.”
In May, 2016, Boyajian also started a crowd-funding Kickstarter campaign titled Where's the Flux that raised over $100,000 for to secure over a year’s worth of professional robotic telescope time to solve the mystery of KIC 8462852. Many of the backers are people who are contributing to scientific research a few dollars at a time. Many of the backers and amateur observers KIC 8462852 are extremely engaged. Boyajian and several other volunteers created a Reddit page just for questions and discussion around the star and new data from it. The page now has over active 4,000 users.
“It’s been great to have that feedback, to see people getting really excited about the science,” Boyajian said.
Citizen science does come with its challenges. Cleaning and synthesizing the KIC 8462852 data collected by amateur observers isn’t trivial. Boyajian has worked with AAVSO to develop detailed instructions for observers to help them collect better data from the star using proper scientific standards and calibrations. The quality of the data collected from amateur observers depends largely on the experience of each observer, and individual observations aren’t ideal for capturing star signals in real-time. But without citizen scientists, Tabby’s Star might never have been discovered, Boyajian would never have started a project to point professional telescopes at the star to observe its strange light dips in real-time.
Only time will tell Boyajian what exactly is passing in front of the most mysterious star in the universe.