Starquakes Might Solve the Mysteries of Stellar Magnetism

That was a shock—and a potential indication that one thing essential was lacking in these fashions: magnetism.

Stellar Symmetry

Last yr, Gang Li, an asteroseismologist now at KU Leuven, went digging by way of Kepler’s giants. He was looking for a mixed-mode sign that recorded the magnetic discipline in the core of a pink large. “Astonishingly, I actually found a few instances of this phenomenon,” he mentioned.

Typically, mixed-mode oscillations in pink giants happen virtually rhythmically, producing a symmetric sign. Bugnet and others had predicted that magnetic fields would break that symmetry, however nobody was capable of make that difficult statement—till Li’s workforce.

Li and his colleagues discovered a large trio that exhibited the predicted asymmetries, and so they calculated that every star’s magnetic discipline was as much as “2,000 times the strength of a typical fridge magnet”—sturdy, however in step with predictions.

However, one of the three pink giants shocked them: Its mixed-mode sign was backward. “We were a bit puzzled,” mentioned Sébastien Deheuvels, a examine creator and an astrophysicist at Toulouse. Deheuvels thinks this consequence means that the star’s magnetic discipline is tipped on its aspect, which means that the approach may decide the orientation of magnetic fields, which is essential for updating fashions of stellar evolution.

A second examine, led by Deheuvels, used mixed-mode asteroseismology to detect magnetic fields in the cores of 11 pink giants. Here, the workforce explored how these fields affected the properties of g-modes—which, Deheuvels famous, could present a solution to transfer past pink giants and detect magnetic fields in stars that don’t present these uncommon asymmetries. But first “we want to find the number of red giants that show this behavior and compare them to different scenarios for the formation of these magnetic fields,” Deheuvels mentioned.

Not Just a Number

Using starquakes to research the interiors of stars kicked off a “renaissance” in stellar evolution, mentioned Conny Aerts, an astrophysicist at KU Leuven.

The renaissance has far-reaching implications for our understanding of stars and of our place in the cosmos. So far, we all know the precise age of only one star—our solar—which scientists decided based mostly on the chemical composition of meteorites that shaped throughout the beginning of the photo voltaic system. For each different star in the universe, we solely have estimated ages based mostly on rotation and mass. Add inside magnetism, and you’ve got a solution to estimate stellar ages with extra precision.