NASHVILLE -- Roger Cohen shifted nervously in his chair Monday as his colleague explained their joint discovery, a mystery object apparently orbiting another star in a never-before-seen configuration.
Cohen stood, shy upon being introduced to reporters. He bowed awkwardly, not sure if that's what he was supposed to do. He spoke under his breath a few times during the presentation and corrected his elder colleague once.
Thin and polite, Cohen looks young, as though he might still be in college. In fact, he just graduated Sunday from Wesleyan University.
Yet, not even in graduate school, Cohen has nailed the discovery of a lifetime.
While working on his senior thesis a few months ago, Cohen was pawing through five years of data on various stars, collected through the grunt work of undergraduates at the university's modest 24-inch (0.6 meter) telescope. One star, called HMW15, appeared to wink partially, dropping in brightness by one-half as if eclipsed by some passing object. But it was the slowest such wink ever measured at any star by any astronomer of any age.
"I nearly fell out of my chair," Cohen said.
He showed the data to William Herbst, a Wesleyan astronomy professor who has some experience with winking stars.
"When I saw the data I knew Roger had found something special," Herbst said. "It was something never seen before." Previously, the longest eclipse of a star had lasted two years. The eclipse of HMW15 was 3-and-a-half years long, "totally amazing," Herbst said.
Herbst presented the discovery here at a meeting of the American Astronomical Society. Cohen sat among the reporters, too green to take the pressure, the professor said.
Herbst detailed how the star faded for about a year, bottomed out, and then brightened again for about a year, then leveled off at its pre-event luminosity. The pattern its changing light leaves on a graph is consistent with that of an eclipse by an object orbiting the star, Herbst said, but he doesn't know what could cause such a long eclipse. It is possibly a cloud of material that might be destined to develop into a planet, he said. It is unlikely to be a star or a foreground object of any sort.
A half-dozen other experts in how dust and planets evolve around other stars had no good suggestions. One of them, a University of Florida astronomy professor, did ask Cohen to consider Florida for grad school, however.
In an interview, Cohen said he hasn't decided his career path. He figures it will probably be astronomy. "This certainly didn't hurt," he said of the discovery.
But Cohen is still young. There are other things on his mind, too. He put in about 5-10 hours a week on the work that led to today's announcement. Meanwhile, he's been playing the drums in four or five bands and studying philosophy, too.
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