PHOTO CREDIT: M. Weiss Artist’s conception illustrating improved angular resolution, as was achieved using a scalable version of the intensity interferometry technique developed at VERITAS.
Gamma-ray Scientists Help Bring Distant Stars into Focus By Amy Oliver, Public Affairs, Center for Astrophysics | Harvard & Smithsonian, Fred Lawrence Whipple Observatory Scientists in the VERITAS Collaboration have measured the angular diameter of stars using Stellar Intensity Interferometry for the first time in nearly 50 years. They have demonstrated both improvements to the sensitivity of the technique and its scalability using digital electronics. Led by astronomers from the University of Utah and the Center for Astrophysics | Harvard & Smithsonian, VERITAS (Very Energetic Radiation Imaging Telescope Array System) scientists measured the angular diameters 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 lightyears from the sun. “A proper understanding of stellar physics is important for a massive range of astronomical fields, from exoplanet studies to cosmology, and yet they are often seen as point sources of light due to their
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great distances from Earth,” said Nolan Matthews, graduate research assistant at the University of Utah. “Interferometry has been widely successful in achieving the angular resolution needed to spatially resolve stars, and we’ve demonstrated the capability to perform optical intensity interferometry measurements with an array of many telescopes that in turn will help improve our understanding of stellar systems.” Michael Daniel, operations manager at VERITAS, added, “Resolving something the size of a coin on the moon is a marvelous thing. Knowing if that coin is a dime or a nickel is something even more special still. If you want that level of detail, then you want intensity interferometry to work on this scale.” VERITAS used all four of its gamma-ray telescopes, located at the Fred Lawrence Whipple Observatory in Amado, Arizona, to increase its coverage and provide greater resolution for observation.
