News

  • Research
  • Astrophysics/Cosmology

In its search for extrasolar planets, the Kepler space telescope looks for stars whose light flux periodically dims, signaling the passing of an orbiting planet in front of the star. But the timing and duration of diminished light flux episodes Kepler detected coming from KIC 846852, known as Tabby’s star, are a mystery. These dimming events vary in magnitude and don’t occur at regular intervals, making an orbiting planet an unlikely explanation. The source of these unusual dimming events is the subject of intense speculation. Suggestions from astronomers, astrophysicists, and amateur stargazers have ranged from asteroid belts to alien activity.  

Now a team of scientists at the University of Illinois at Urbana-Champaign—physics graduate student Mohammed Sheikh, working with Professors Karin Dahmen and Richard Weaver—proffer an entirely novel solution to the Tabby’s star puzzle. They suggest the luminosity variations may be intrinsic to the star itself.

  • Research
  • Condensed Matter Physics

Apparently, size doesn't always matter. An extensive study by an interdisciplinary research group suggests that the deformation properties of nanocrystals are not much different from those of the Earth's crust.

"When solid materials such as nanocrystals, bulk metallic glasses, rocks, or granular materials are slowly deformed by compression or shear, they slip intermittently with slip-avalanches similar to earthquakes," explained Karin Dahmen, a professor of physics at the University of Illinois at Urbana-Champaign. "Typically these systems are studied separately. But we found that the scaling behavior of their slip statistics agree across a surprisingly wide range of different length scales and material structures."

  • Accolades
  • Condensed Matter Physics

Dahmen’s infectious enthusiasm for physics has made her a fine lecturer, but her commitment to teaching goes far beyond the classroom. She has one of the largest undergraduate research groups in our department, regularly mentoring four to six undergraduates at a time, involving them in independent, hands-on projects, and providing them with precious personal attention that prepares them well for future success. Three of the undergraduate women that she originally mentored have gone on to obtain doctoral degrees in physics, chemistry, and theoretical astrophysics.