By Shannon Hall
Georgios Dimitriadis thought he had botched the data. It was late on a Friday night and the University of California, Santa Cruz, astronomer was the last one in the office. He had been waiting anxiously for NASA’s planet-hunting Kepler space telescope to stream a batch of data toward Earth—not because he wanted to scour the observations for signs of exoplanets but because he was looking for a supernova.
See, Kepler was designed to do one thing remarkably well: Monitor stars so closely that it could catch tiny flickers in brightness. That made it ideal for finding exoplanets (that obscure their host stars’ light)—as well as making an array of other observations such as recording the rise and fall of light emitted during a star’s death throes. So when Kepler’s mission was extended, astronomers decided the telescope should scour more than 20,000 galaxies in order to catch as many supernovae as possible. And when one erupted in a spiral galaxy only 170 million light-years away last January, Dimitriadis knew it would be the best look yet at the first moments behind the cosmic detonation.
But the data provided a better record than he had even hoped for. “I thought I had done something wrong—not because there is noise, but because it was so good,” Dimitriadis says, explaining astronomers typically miss the first few days or even weeks after a supernova explodes and then monitor it once every night. That gives them relatively few data points. But here astronomers had images before the explosion and every 30 minutes thereafter. “I had never seen something like this before,” he says. What is more: The supernova’s brightness rose sharply during those early moments, creating an unexpected “bump” in the graph of its changing light over time, called a light curve. Dimitriadis circled that bump in red and drew an arrow toward it with three question marks before sending the light curve off to his collaborators. They have since analyzed that bump—in an attempt to determine the eruption’s hidden trigger—in a new paper accepted for publication in The Astrophysical Journal Letters and available online.
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