Stellar Evolution
planetary nebula
a cloud of gases and dust that surrounds a white dwarf
protostar
a collection of gases that begins to heat, ultimately reaching the density and temperature at which hydrogen fusion can begin
white dwarf
a former red giant star that has completed helium fusion, collapsed, and is cooling
If the core of a supernova contains about one solar mass, the core will become a _____.
a neutron star
supernova
a red supergiant that collapses and explodes after it has expended its fuel for nuclear fusion reactions
black hole
a region of space with matter so dense that light cannot escape it
red giant
a star that has expended its hydrogen fuel, expanded in size, and begun fusing helium or heavier elements in its core
main sequence star
a star that is fueled by hydrogen fusion into helium
If the core of a supernova explosion contains three or more solar masses of matter, the core will most likely become a _____.
black hole
nebula
enormous cloud of gas and dust in space
A neutron star that spins and emits beams of energy is called a _____.
pulsar
Small main sequence stars may continue undergoing hydrogen fusion for hundreds of billions of years. These stars are called _____.
red dwarfs
After its main sequence existence, a medium-sized star, like our Sun, will become a _____.
red giant
If a star is massive, it will remain in the main sequence _____ a smaller star.
shorter than
red dwarf
small main sequence star that fuses hydrogen for tens or hundreds of billions of years
A protostar is _____.
the stage before a star becomes a main sequence star
When a red giant completes helium fusion and collapses, it becomes a ______.
white dwarf
