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Probing a centuries-old mystery in the stars

Atop Mt. Wilson, an astronomer hopes to find the key to Epsilon Aurigae, which for nearly two centuries has baffled astronomers with its fluctuations of light every 27.1 years.

January 20, 2011|By Thomas Curwen, Los Angeles Times
  • Brian Kloppenborg hopes for a clear, calm night on Mt. Wilson in his attempt to unlock the secret of Epsilon Aurigae.
Brian Kloppenborg hopes for a clear, calm night on Mt. Wilson in his attempt… (Mark Boster / Los Angeles…)

As night settles upon Mt. Wilson, stars rise out of the December darkness and the wind begins to howl.

Brian Kloppenborg looks overhead. There's Polaris and in the northeast, the Big Dipper, all bright and twinkling to the naked eye, but to the telescopes on this summit, they are smudges, their light blurred by the blustery streams of air and dust. If this keeps up, observing tonight will be impossible.

"There," he says. "It's just to right of Capella. See it?"

He aims a flashlight high above a horizon of swaying pines and firs in the direction of a flickering star, faint enough to be easily overlooked.

"That's it — Epsilon Aurigae," he says with an almost paternal air.

If he's disappointed by the conditions tonight, he's not showing it. He'll be up here for another night and he's been lucky so far. Since 2008, he has studied this distant neighbor of Earth with great success.

Lying in the swirls of the Milky Way 2,000 light-years away, Epsilon Aurigae (pronounced EP-si-lon au-RYE-gee) has long puzzled observers with its strange fluctuations of light. After seven visits to this summit, using one of the most sophisticated arrays of telescopes in the world, Kloppenborg, with the help of other astronomers, is slowly unraveling the mystery of this star.

The findings so far have earned him a small measure of fame — publication in the science journal, Nature — and have lent Epsilon Aurigae celebrity status in astronomy circles. It is the focus of both amateur and professional astronomers around the world, a lyric in a rock ballad, "We Are the Stars" and inspiration for artwork that would make Spock proud.

Once merely an odd sounding name in the broad panoply of night, Epsilon Aurigae came to prominence almost 200 years ago when a sharp-eyed government minister looked above the German countryside and noticed something strange in the crowded sky. The star, fifth brightest in the constellation Auriga, had dimmed.

"Has anyone else seen this?" Johann Fritsch wrote in letter to a publisher of star almanacs. The question soon became a challenge to the astronomers of the day, who in time recorded that every 27.1 years, Epsilon Aurigae lost half its brightness for nearly two years.

They tried to explain the phenomenon as a system of stars, one orbiting the other in a long, leisurely ellipse, but something didn't make sense. When one of the objects passed in front of the other, the light didn't behave as it did in other binary systems.

Perhaps, the astronomers argued, the eclipse was caused by something other than a star, and with each eclipse, new theories tried to explain the fluctuations of light.

A swarm of meteorites, said one astrophysicist.

A black hole, said another.

A large and dusty cloud.

Or a disk like the rings of Saturn.

But no one knew because from the perspective of Earth, Epsilon Aurigae, like all stars, is not an object but a pinpoint of light whose specific dimensions and shape could only be derived mathematically, and sometimes the numbers can be off.

If only it could be seen more clearly.


Kloppenborg steps inside a small building on Mt. Wilson. Sitting in an alcove in the glow of six computer monitors, P.J. Sallave-Goldfinger operates the telescopes that he will use. She isn't about to open any of them. Dust, flying pine needles and condensation might spoil the mirrors' surfaces.

Perched more than a mile above Los Angeles, Mt. Wilson has always been valued for its location. More nights than not, the air from the Pacific flows smoothly over the mountains, and a number of universities maintain telescopes here, including Georgia State University with its Center for High Angular Resolution Astronomy.

The CHARA array is an optical interferometer, a fancy name for six, widely spaced telescopes and a labyrinth of trolleys, mirrors and vacuum-sealed conduits that brings starlight into stunningly precise resolution. If someone were to build a Wal-Mart on Mars, CHARA could count the parking spaces.

Focused on a star system 2,000 light-years away, the array allows astronomers like Kloppenborg to define its specific properties.

"We are in a period when it is becoming possible to see star systems in detail," says science writer Timothy Ferris. "One reason these studies are important is because they shed light on how our star and our planet got here — and the story of how the Earth got here is also the story of how human beings came to be here."

When the article in Nature came out in April, it was described by the distinguished astrophysicist Edward Guinan as a "turning point" in the understanding of Epsilon Aurigae. Kloppenborg was lead author, a heady accomplishment for any scientist, let alone a 27-year-old graduate student at the University of Denver.

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