The Star lifecycle
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Stars expand as they grow old. As the core runs out of hydrogen and then helium, the core contacts and the outer layers expand, cool, and become less bright. This is a red giant or a red super giant (depending on the initial mass of the star). It will eventually collapse and explode. Its fate is determined by the original mass of the star; it will become either a black dwarf, neutron star, or black hole.
NEBULA
A nebula is a cloud of gas (hydrogen) and dust in space. Nebulae are the birthplaces of stars.
STAR
A star is a luminous globe of gas producing its own heat and light by nuclear reactions (nuclear fusion).
RED GIANT
This is a large bright star with a cool surface. It is formed during the later stages of the evolution of a star like the Sun, as it runs out of hydrogen fuel at its centre.
RED DWARF
These are very cool, faint and small stars, approximately one tenth the mass and diameter of the Sun.
WHITE DWARF
This is very small, hot star, the last stage in the life cycle of a star like the Sun.
SUPERNOVA
This is the explosive death of a star, and often results in the star obtaining the brightness of 100 million suns for a short time.
BLACK HOLES
Black holes are believed to form from massive stars at the end of their life times. The gravitational pull in a black hole is so great that nothing can escape from it, not even light.
NEBULA
A nebula is a cloud of gas (hydrogen) and dust in space. Nebulae are the birthplaces of stars.
STAR
A star is a luminous globe of gas producing its own heat and light by nuclear reactions (nuclear fusion).
RED GIANT
This is a large bright star with a cool surface. It is formed during the later stages of the evolution of a star like the Sun, as it runs out of hydrogen fuel at its centre.
RED DWARF
These are very cool, faint and small stars, approximately one tenth the mass and diameter of the Sun.
WHITE DWARF
This is very small, hot star, the last stage in the life cycle of a star like the Sun.
SUPERNOVA
This is the explosive death of a star, and often results in the star obtaining the brightness of 100 million suns for a short time.
BLACK HOLES
Black holes are believed to form from massive stars at the end of their life times. The gravitational pull in a black hole is so great that nothing can escape from it, not even light.