Gamma-ray telescopes measure diameters of distant stars

By reviving a technique capable of combining specialized gamma-ray telescopes to one giant virtual instrument, scientists have measured the diameters of individual stars hundreds of light-years away. The team used the four VERITAS telescopes (Very Energetic Radiation Imaging Telescope Array System) in the US as one combined instrument to determine the size of Beta Canis Majoris—a blue giant star located 500 light-years from the sun—and Epsilon Orionis—a blue supergiant star located 2,000 light-years from the sun. The Stellar Intensity Interferometry technique, demonstrated for the first time nearly 50 years ago, could be a secondary use for other gamma-ray observatories as well, including the upcoming Cherenkov Telescope Array (CTA). The team led by astronomers from the Harvard & Smithsonian Center for Astrophysics (CfA) and the University of Utah and including scientists from DESY report their findings in the journal Nature Astronomy.

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