POSS-II / STSCI / CALTECH / PALOMAR OBSERVATORYpCARBON DWARF The slightly orange star at the center of this image
is G77-61, the fi rst carbon dwarf discovered. The image spans half a
degree in Taurus. G77-61 remains the brightest and nearest known
example of a carbon dwarf.58 FEBRUARY 2020 • SKY & TELESCOPE
O
f 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 giants, 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 fi rst, 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 sheddingStars that shouldn’t even exist may soon
offer new clues to both the ancient universe
and the galaxy’s birth.THE STARS THAT SHOULDN’T BEby Ken Croswell
Dwarf