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In space, no one can hear the stars. Sounds can’t travel through a vacuum, but stars nevertheless give off subsonic notes caused by vibrations created deep inside their structures. And an astrophysicist has been working on how this stellar symphony can teach us about the interior of stars.

Jacqueline Goldstein, a graduate student in the University of Wisconsin-Madison astronomy department, has investigated how the shape of different types of stars affects the frequencies they give off. “A cello sounds like a cello because of its size and shape,” she explained in a statement. “The vibrations of stars also depend on their size and structure.”

The vibrations occur when deep within their cores, stars fuse hydrogen into heavier elements. This process causes hot plasma gases to vibrate, which makes the light from the star flicker. By examining the flickering of stars and comparing it to simulations, astrophysicists can learn about the stars’ interior structure.

In particular, Goldstein looked at stars larger than our Sun. “Those are the ones that explode and make black holes and neutron stars and all the heavy elements in the universe that form planets and, essentially, new life,” she explained. “We want to understand how they work and how they affect the evolution of the universe. So these really big questions.”

Telescopes can “listen in” on the vibrations of stars by recording their fluctuations, then this data is compared to simulated models of stars created using open-source software. If the real data differs from the simulations, this indicates that the scientists’ assumptions need to be adjusted as the models are not fully capturing what is going on inside the stars.

The research could benefit from future findings of planet-hunting satellites like TESS, which was launched last year and has already discovered its first exoplanets.

Goldstein is developing new software to analyze the TESS data and create more detailed simulations. “What TESS is doing is looking at the entire sky,” she said. “So we’re going to be able to say for all the stars we can see in our neighborhood whether or not they’re pulsating. If they are, we’ll be able to study their pulsations to learn about what’s happening beneath the surface.”

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