Washington College Magazine
HD 189733's planet is slightly larger than Jupiter. Tim Pyle at NASA created this artist's rendition of the planet, which is extremely close to its sun.
Ellyn Baines '00 worked closely on her dissertation with Hal McAlister, head of GSU's Center for High Angular Resolution Astronomy.
Where No One Has Gone Before
Ellyn Baines '00 has kept her eyes on the stars since graduating from Washington College—in fact, she has led a scientific team in a pioneering astronomical discovery.
Physics professor Satinder Sidhu could not be more jubilant. His former student, Ellyn Baines '00, is one of the astronomers at Georgia State University's Center for High Angular Resolution Astronomy (CHARA) who performed a feat no scientist had achieved before: inspecting a host star with a transiting planet in a distant constellation, and using planet-to-star-radii ratio known from photometric studies, they were able to directly measure the size of a planet not in our solar system.
By cracking the code to directly measure the diameter of star HD 189733 (it's in the constellation Vulpecula, for you stargazers out there), Baines' team also succeeded in determining the diameter of the planet revolving around this distant sun. The planet was discovered by an international team of astronomers in 2005. It is approximately 63 light years away.
As science manages to look beyond our own solar system with ever-increasing accuracy, the first-ever measurement of a planet beyond our own sun's family constitutes a significant milestone. "I got to be part of this project through my dissertation work, and it was a case of being at the right place at the right time and grabbing the opportunity when it came," said Baines, who majored in physics and art at WC before earning her master's degree in physics and Ph.D. in astronomy at GSU. "It was amazingly fun when the idea worked and we found we'd done something never done before."
So how on earth did Baines and crew pull off such a galactic feat? They managed it with the heavy hardware at the heart of CHARA's flagship project: an array of six high-powered, finely precisioned telescopes fanned out across 330 meters atop Mount Wilson, CA—the celebrated CHARA Array.
When the paths of the individual telescopic beams are matched, the Array acts like a single coherent über-telescope (more powerful than the largest telescope that could be built) for the purposes of achieving exceptionally high resolution. The Array is capable of resolving details equivalent to the size of a nickel seen from a distance of 10,000 miles. As GSU's Web site notes, "The CHARA Array is arguably the most powerful instrument of its kind in the world."
With this sort of instrumental firepower, and in light of the recent astronomical breakthrough, the CHARA project seems likely poised for further exciting discoveries. "I hope this will be the first of many such measurements," said Baines, "because everything we learn about other worlds tells us a little bit more about our own."
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