Dwarf Carbon Stars

OF THE MANY CHEMICAL ELEMENTS that stars create, none is more vital to terrestrial life than carbon. About half the carbon in your body arose from red giant stars, which minted the element in their interiors and then dredged it up to their surfaces, transforming themselves into carbon stars. They cast the element away when they ejected their carbon-coated atmospheres and became white dwarfs.

As if beckoning their progeny on Earth, carbon stars boast beautiful ruby hues that have long attracted observers: “the most intense crimson, resembling a blood-drop,” wrote 19th-century astronomer John Russell Hind of the carbon star R Leporis. Although this stellar gem is known as Hind’s Crimson Star, William Herschel spotted it first, calling it “A bright garnet star …a most beautiful colour” four years after discovering the planet Uranus.

Giant carbon stars look even redder than ordinary red giants for two reasons. First, carbon compounds soak up the stars’ blue and violet light. Second, the stars are shedding their carbon-rich atmospheres, enshrouding themselves in dust that further