How does a star affect the makeup of its planets? And what does this mean for the habitability of distant worlds? Carnegie’s Luke Bouma recently revealed a new way to probe this critical question—using naturally occurring “space weather stations” that orbit at least 10 percent of M dwarf stars during their early lives. He and collaborator Moira Jardine of the University of St. Andrews took “spectroscopic movies” of young, rapidly rotating stars called complex periodic variables, which experience recurring dips in brightness. It turns out that these blips are due to large clumps of cool plasma that are being dragged around with the star by its magnetic field. We know that in our own Solar System, planets are affected by solar winds, magnetic storms, and other space weather coming from the Sun. However, until now, astronomers weren’t able to observe these kinds of phenomena in other systems. Looking ahead, plasma features like this will give astronomers a way to know what’s happening to the material near the stars that host them—including where it’s concentrated, how it’s moving, and how strongly it is influenced by the star’s magnetic field. Bouma described the work as the perfect example of a “serendipitous discovery,” something unlooked for but certain to shape new research programs in the years ahead.
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