In the February article, “New light on our Sun’s fate,” astrophysicist Jason Kalirai explains how stars like the Sun lose mass through their evolution. Such a star pulsates during various life stages, shedding material as it does so. Near the end of its life, it also blows off a substantial amount of its outer layers, which amounts to anywhere from 30 to 80 percent of the star’s original mass. Radiation from the star’s leftover dense core — now called a white dwarf — causes the shed material to glow. The result: a beautiful planetary nebula.
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