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SUDDEN DEATH ▶
Ageing stars with eight or more times
the mass of the Sun swell into enormous,
unstable supergiant stars, which can end
their lives in a sudden and spectacular
explosion known as a supernova. The
exploding star creates an extremely hot
gas cloud called a supernova remnant,
while its core can collapse to become a
rapidly rotating, very dense pulsar or
a black hole (where the core collapses
in on itself under gravity until it is a
hole in space). The material dispersed
into space forms clouds, which in turn
can give birth to new stars.▲ DYING STARS
When a star with a mass of up to
eight times that of the Sun runs
out of hydrogen, it swells up,
cools, and becomes a red giant.
Eventually, the giant star ejects
its outer layers and becomes a
planetary nebula. The ejected gas
slowly disperses, leaving behind
a white dwarf – the tiny, slowly
cooling core of the original star.Crab PulsarCrab Nebula, a supernova remnantSupernova 1987AEjected material
from Eta Carinae,
an old star expected
to go supernova
at any timeRed supergiant V838 Monocerotis
surrounded by a cloud of dust and gasBetelgeuse, a
red supergiantHelix NebulaCat’s Eye Nebula,
with a white dwarf
visible at its centre132_133_Stars.indd 133 03/01/19 12:10 PM