Meet Baylor’s expert on white dwarf stars

To understand why scientists are interested in white dwarf stars, it helps to think of fossils, or rings on a tree.

Dr. Barbara Castanheira, assistant professor of physics and astronomy at Baylor, has long studied white dwarf stars — the dense, collapsed core of a dying star. White dwarf stars are of interest to scientists, perhaps somewhat counterintuitively, because they can tell us about early star formation despite being in the final stages of their life cycle — a cycle which lasts billions of years, beyond the scope of human study from start to finish. As opposed to the bright stars visible in the sky, white dwarf stars have shrunk in size and no longer actively produce energy. As their remaining energy burns out, they have a story of great interest to science.

The National Science Foundation (NSF) has long supported Castanheira’s work, and she’s published results of her findings in leading astrophysics journals. Her expertise has also led to interviews with local media regarding space phenomena like the 2024 solar eclipse, but it’s white dwarf stars that have become the focus of her career.

Castanheira explains that these stars actually produce an imprint of each stage of their evolution. That means that while the star’s life cycle may be ending, the record it contains tells scientists about the star’s formation and its entire life — not unlike the record found in rings within a large tree. Star formation yields clues about the age of the universe going backward, and how the solar system might someday behave going forward. It’s like a puzzle Castanheira puts together through her research.

“We are just here trying to understand how things work,” she told the Baylor Lariat. “The universe is fascinating. Look at the stars, like Stephen Hawking said. Look at the stars. It’s always beautiful. There’s always something just fascinating.”

Sic ’em, Dr. Castanheira!