The surprising chemistry at the core of a white dwarf

NASA’s Kepler space observatory, which has circled the Sun for nearly nine years in an Earth-trailing orbit, is best known as a planet hunter. By continuously observing variations in the brightness of 150 000 stars in its fixed field of view, it can detect the telltale periodic dimming caused by transiting exoplanets. But Kepler’s observations are also a treasure trove for asteroseismologists, who analyze stars’ intrinsic pulsations to tease out the physical properties of stellar interiors. Such studies have yielded precise estimates of stellar masses, temperatures, and internal rotation speeds. (See the article by Conny Aerts, Physics Today, May 2015, page 36.)