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Astronomy in the News

Mercury Winter 2010 Table of Contents


An artistic representation of one model of the Epsilon Aurigae system as seen at high inclination.

An artistic representation of one model of the Epsilon Aurigae system as seen at high inclination.
Credit: Citizen Sky / Nico Camargo.

2010: Year of the Baffling Eclipse

AAVSO

In August 2009, amateur and professional astronomers reported that the bright star Epsilon Aurigae had begun to lose brightness for the first time in 27 years. It is believed that the dimming of the star’s light is caused by an eclipsing object of an unknown nature.

The first phase of the eclipse involved a dramatic drop in brightness over the course of a few months beginning in August. Professional and amateur astronomers teamed up to monitor the eclipse and have announced that this critical phase ended around New Year’s Day 2010.

"We have increasing evidence that a dark disk of material has moved in front of our view of Epsilon Aurigae," said Dr. Robert Stencel, scientific advisor for the project. "But the exact shape and make up of the disk has been unknown, but will be better defined soon."

Even during the eclipse, the star is so bright that sensitive equipment in professional observatories can have trouble monitoring its brightness in the optical wavelengths. Furthermore, large telescopes cannot afford to monitor one star continuously. This is where amateurs and citizen scientists step in.

"Amateurs are the ideal astronomers for this project. Either with their naked eyes or with digital cameras, they have proven that they can record professional quality data," said Dr. Arne Henden, director of the American Association of Variable Star Observers (AAVSO) and principal investigator of the project.

If past eclipses are any guide, this dark stage will last nearly 18 months, followed by a rapid return to its normal brightness in the first half of 2011.


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