Citizen Sky Invites Public to Help Resolve a Stellar Mystery

25 August 2009

This fall a bright star will begin a puzzling transformation that only happens every 27 years. To help study this event, astronomers have launched a new citizen science project called "Citizen Sky" at www.CitizenSky.org.

Epsilon Aurigae is a bright star that can be seen with the unaided eye even in bright urban areas of the Northern Hemisphere from fall to spring. This fall it is predicted to gradually lose half its
brightness until early winter. It will remain faint during all of 2010 before slowly regaining its normal brightness by the summer of 2011.

Since its discovery in 1821, the cause of this dip in brightness has remained a mystery to astronomers. But this time they have a powerful new resource to help study the upcoming event: thousands of citizen scientists.

"This star is too bright to be observed with the vast majority of professional telescopes, so this is another area where public help is needed," said Dr. Arne Henden, director of the American Association of Variable Star Observers (AAVSO).

Supported by a three-year grant from the National Science Foundation, Citizen Sky will recruit, train, and coordinate public participation in this project. What makes this project different from previous citizen science projects is its emphasis on participation in the full scientific method. Participants are not being asked simply to collect data. They will also be trained to analyze data, create and test their own hypotheses, and to write papers for publication in professional
astronomy journals. Participants can work alone on all phases of the project or they can focus on one stage and team up with others.

"Citizen science can be much more than data collection. Participants often have real-world experience and/or advanced degrees in areas that can be applied to astronomy. Our goal is to introduce the public to authentic science and at the same time use this talent to help
astronomers," Henden said.

The lead astronomer for this project is Dr. Robert Stencel, the William Herschel Womble Professor of Astronomy at Denver University. Dr. Bob, as the amateur astronomy community knows him, studied the last event in 1982-84 while working at NASA. "This is truly an amazing
star system. It contains both a supergiant star and a mysterious companion. If the supergiant was in our solar system, its diameter would extend to Earth, engulfing us," Stencel said. "The companion only makes its presence known every 27 years and is a type of ‘dark matter' in that we indirectly detect its presence but don't know what it is.

"To make things even more fun, we also have some evidence of a substantial mass, perhaps a large planet, spiraling into the mysterious dark companion object. Observations during the upcoming eclipse will be key to understanding this and predicting what will happen if the putative planet does eventually fall into the star," Dr. Bob added.

Citizen Sky is a collaboration of the AAVSO, Denver University, Adler Planetarium and Astronomy Museum, Johns Hopkins University, and the California Academy of Sciences. The United Nations and the United States Congress have both endorsed 2009 as the International Year of Astronomy (IYA2009). Citizen Sky was developed as part of the coordinated United States' IYA2009 effort.

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