Inner workings of a white dwarf star

Nature : The period with which the brightness of a pulsating star oscillates depends on the specific structure of its interior.Using asteroseismology , astronomers can measure the temporal frequency spectra of pulsating stars—the seismograms of astronomers—to infer information about the stars’ otherwise unobservable interior.For example, rotating pulsating stars “sound” different from nonrotating stars: because rotating stars cannot preserve their spherically symmetric shape during pulsation, their temporal frequency spectrum is marked by nonradial modes of pulsation.This property has allowed astronomers to measure the spin rates of pulsating white dwarfs—stellar remnants of relatively low-mass stars. But until this week, they hadn’t been able to measure the internal rotation profiles of these stars.In a paper in Nature S. Charpinet, G. Fontaine, and P. Brassard present the first evidence that a newly born white dwarf, dubbed PG 1159-035 , rotates at the same rate for almost the entire depth of its body. Related Link Seismic evidence for the loss of stellar angular momentum before the white-dwarf stage