Starquakes Might Solve the Mysteries of Stellar Magnetism
WiredClose to a star’s heart, magnetic fields play crucial roles in chemical mixing in the star’s interior, which in turn affects how a star evolves. “We don’t include magnetism in stellar modeling,” said Lisa Bugnet, an astrophysicist at the Institute of Science and Technology Austria who developed methods for studying magnetic fields inside red giants. In the same way that seismic waves rippling through Earth’s interior can be used to map the planet’s subterranean landscape, stellar oscillations open a window into a star’s innards. For stars like our sun, p-modes dominate their observable oscillations; their g-modes, which are affected by internal magnetic fields, are too weak to detect and can’t reach the star’s surface. Studying mixed modes revealed that red giant cores rotate much more slowly than the star’s gaseous envelope, contrary to what astrophysicists had predicted.
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