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Updated: Jul 10, 2026

Bringing the Visible Universe into Focus with Robo-AO
Published on: February 12, 2013
Imaging the surface of Altair
John D Monnier1, M Zhao, E Pedretti
1Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA. monnier@umich.edu
Abstract:
Spatially resolving the surfaces of nearby stars promises to advance our knowledge of stellar physics. Using optical long-baseline interferometry, we constructed a near-infrared image of the rapidly rotating hot star Altair with a resolution of <1 milliarcsecond. The image clearly reveals the strong effect of gravity darkening on the highly distorted stellar photosphere. Standard models for a uniformly rotating star cannot explain our findings, which appear to result from differential rotation, alternative gravity-darkening laws, or both.
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