Giant stars bare their whirling hearts
DEC 09, 2011
DOI: 10.1063/PT.5.025758
Science : Cool giant stars spin slowly on their surfaces, but what about their cores? Paul Beck of the Catholic University of Leuven in Belgium and colleagues have reported that the cores of three yellow giant stars, each 20% to 50% more massive than our Sun, spin at least ten times faster than their surfaces. Beck’s team studied data from NASA’s Kepler spacecraft, which monitors the variations in starlight that occur when planets pass in front of their star. Oscillations within a star—called asteroseismological vibrations—can also cause starlight to vary, and they provide information about stars’ internal structure. The discovery implies that our Sun’s core will also spin faster than its surface when it becomes a giant; this may affect how it sheds its outer atmosphere and transforms from a red giant into a white dwarf.
© 2011 American Institute of Physics
