There’s a mystery in the night sky that you can help solve.
Every 27 years, in the constellation called Auriga (the charioteer), a bright star designated epsilon goes dim for nearly two years. Epsilon Aurigae is a “binary eclipsing variable star,” which is astronomer-speak for a star that appears to change brightness as an orbiting companion body periodically passes by, “eclipsing” and blocking the primary star’s light. The most recent eclipse of epsilon Aurigae started in August 2009 and will continue into next summer.
The mystery, which has baffled astronomers since the binary system was first noted in 1821, is this: What exactly is epsilon Aurigae’s companion? The companion gives off no light at all, and, to add to the mystery, epsilon Aurigae seems to brighten slightly in the middle of its two-year eclipse. All of this has led researchers to propose that the companion is a “transparent shell star” or a thin disk of material with a gap in the center. Or maybe two smaller stars in the midst of a disk of matter. So far, they just don’t know what it is.
What astronomers need in order to solve the puzzle is many, many more eyes to watch epsilon Aurigae as it fades and brightens. Naked eyes, to be exact, because the star is too bright for most telescopes. Such observations, carefully analyzed, can reveal the masses, sizes, and orientations of the star and its companion—all details that help clarify the architecture of the binary system.
So, last year, the American Association of Variable Star Observers started a citizen science effort to recruit those eyeballs. Called Citizen Sky, the project now has about 2,000 registered volunteers; to date, the few hundred most active have contributed 3,785 observations of the current eclipse.
Though still new, the results are promising, says project creator and AAVSO assistant director Aaron Price: “So far we have a beautiful light curve of the epsilon Aurigae eclipse that has helped professionals build a better model for the system causing the eclipse.”
Price and the rest of folks behind Citizen Sky take their volunteers very seriously. Participants train on a 10-star tutorial to get started on data collection and analysis. They are encouraged to develop their own research questions and to form teams, with the help of a professional, to address those hypotheses. And they have been invited to attend workshops, put on by the project leaders, on binary-star science and on data analysis and writing research papers. Through a blog, forums, chat, and newsletters, volunteers keep in touch with each other and with the scientists. “Part of our core mission is to engage participants in every stage of the scientific process–not just data collection,” says Price.
In fact, Price, who is a PhD candidate in science education at Tufts, is writing his dissertation on the impact of the project on the participants’ science literacy. One surprising result, he says: “Collaboration and communication between participants is key.”
Soon, Citizen Sky will have another tool for educating citizen scientists. Guustaaf Damave, an astronomy buff and filmmaker based in Washington state, is putting the finishing touches on an hour-long documentary about the project. It’s called, appropriately, “Mystery in the Sky.”
Like the Citizen Sky organizers, Damave takes the long view, using the film to explore not only the project, but the science of binary star systems and the scientific method itself. In addition to the science leaders of Citizen Sky, such as lead scientist and Denver University astronomer Robert Stencel, the film features volunteer Alice Few, an astronomy podcaster and member of the Tacoma Astronomical Society. “Ultimately, it’s for all the citizen scientists out there,” says Damave.
And all you citizen scientists out there can help make sure the film is released. Damave is asking for contributions to help finish and distribute the DVD, which he plans to sell on Amazon. He needs a total of $1,600 in pledges by October 2 to fund his effort. As of today, he has $1,205. Anyone who pledges $15 receives a copy of the film.