<p><strong>Epsilon Aurigae, a <a id="lg-h" title="star" href="http://science.nationalgeographic.com/science/space/universe/stars-article.html">star</a> 2,000 light-years away</strong><strong>, is eclipsed by a dark, dusty disk in an artist's conception. </strong></p><p>Since the 1820s astronomers have seen Epsilon Aurigae get eclipsed by a mysterious companion for 18 months every 27 years. In fact, <a id="a8x8" title="the latest eclipse of the yellow supergiant star began on January 1, 2010" href="http://news.nationalgeographic.com/news/2010/01/100105-star-eclipse-giant-disk-don-hoard.html">the yellow supergiant star was fully eclipsed on January 1, 2010</a>.</p><p>The nature of the eclipsing object has been a mystery, with theories suggesting everything from a <a id="q5.d" title="black hole" href="http://science.nationalgeographic.com/science/space/universe/black-holes-article.html">black hole</a> to a dusty nebula. Recent studies have suggested that the unseen object is a star surrounded by a massive, dusty disk—and that the two stars orbit each other, forming what's called a binary system.</p><p>Now, new pictures of Epsilon Aurigae, to be published in the April 8 issue of the journal <em><a id="fsyd" title="Nature" href="http://www.nature.com/nature/index.html">Nature</a></em>, seem to confirm the binary-disk theory. The images show that the disk is "a much longer, thinner cigar than most artists tend to illustrate," said study co-author <a id="wd-8" title="Robert Stencel" href="http://mysite.du.edu/~rstencel/">Robert Stencel</a>, a University of Denver astronomer.</p><p><em>—Anne Minard</em></p>

Mystery Disk at Epsilon Aurigae

Epsilon Aurigae, a star 2,000 light-years away, is eclipsed by a dark, dusty disk in an artist's conception.

Since the 1820s astronomers have seen Epsilon Aurigae get eclipsed by a mysterious companion for 18 months every 27 years. In fact, the yellow supergiant star was fully eclipsed on January 1, 2010.

The nature of the eclipsing object has been a mystery, with theories suggesting everything from a black hole to a dusty nebula. Recent studies have suggested that the unseen object is a star surrounded by a massive, dusty disk—and that the two stars orbit each other, forming what's called a binary system.

Now, new pictures of Epsilon Aurigae, to be published in the April 8 issue of the journal Nature, seem to confirm the binary-disk theory. The images show that the disk is "a much longer, thinner cigar than most artists tend to illustrate," said study co-author Robert Stencel, a University of Denver astronomer.

—Anne Minard

Illustration by Brian Thieme and courtesy www.citizensky.org

First Pictures: Mystery Disk Eclipses Star

New pictures confirm that a dark disk is responsible for the star Epsilon Aurigae's regular, 18-month-long eclipses. Also: how to see it in the night sky.

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