3017051
Descrição
Mapa Mental por tiaslavin99, atualizado more than 1 year ago
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Criado por tiaslavin99
mais de 9 anos atrás
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Life cycle
of stars
- How is a
star formed
- 1. Gravity pulls
the dust and gas
together
- 2. As the gas joins
together it gets hot. A
star forms when it is
hot enough for a
nuclear reaction to
take place. This
releases energy and
keeps the star hot
- 3. During the 'main sequence' period
of its life cycle, a star is stable
because the forces in it are
balanced. The outward pressure
from the expanding hot gases is
balanced by the force of the star’s
gravity. Our Sun is at this stable
phase in its life.
- 4.Gravity pulls smaller
amounts of dust and gas
together, which form
planets in orbit around
the star.
- 1. Gravity pulls
the dust and gas
together
- What causes a
star to reach a
certain size
- The star provide an outward
pressure to balance gravity by
pulling everything inwards.
Eventually the hydrogen begins to
run out and that causes the star to
then swirl.
- The star provide an outward
pressure to balance gravity by
pulling everything inwards.
Eventually the hydrogen begins to
run out and that causes the star to
then swirl.
- What does it use
for a fuel source?
- Stars use hydrogen atoms
formed in their core for
energy until the hydrogen
runs out.
- Stars use hydrogen atoms
formed in their core for
energy until the hydrogen
runs out.
- What happens at
the end of its life?
- What happens at the end of a
stars life depends on the size of
the star. When a star has used
up all the hydrogen 'fuel' in its
core, the core contracts and no
more energy is produced
- Medium
sized stars
- when the core of a medium sized
stars such as our sun contract6s the
outer part expands. It then cools and
changes from yellow to red making
the star a red giant. While the sun is
in its red giant phases, shells of gas
are thrown out. These are called
planetary nebulas.
- The core of the original star shrinks
until it is about the size of the earth.
This is a white dwarf, it is very hot and
shines very brightly. It is not making
energy so it eventually cools down.
This causes it to change from white
through yellow and red to black. This
becomes a black dwarf
- when the core of a medium sized
stars such as our sun contract6s the
outer part expands. It then cools and
changes from yellow to red making
the star a red giant. While the sun is
in its red giant phases, shells of gas
are thrown out. These are called
planetary nebulas.
- Massive stars
- A massive star uses up all its hydrogen in a few
million years. The core starts to contract and
the outer part expands as a supergiant. The
core suddenly collapses and the whole star
explodes. This explosion is called a supernova
and the small remaining core is called a neutron
star or a black hole if it is really massive. The
material thrown out as the core explodes,
collide with gas and dust in space and forms a
glowing cloud of gas called a supernova
remnant. Over a period of time the supernova
remnant joins with other dust and gas in space.
As gravitational forces act a new star is formed.
- A massive star uses up all its hydrogen in a few
million years. The core starts to contract and
the outer part expands as a supergiant. The
core suddenly collapses and the whole star
explodes. This explosion is called a supernova
and the small remaining core is called a neutron
star or a black hole if it is really massive. The
material thrown out as the core explodes,
collide with gas and dust in space and forms a
glowing cloud of gas called a supernova
remnant. Over a period of time the supernova
remnant joins with other dust and gas in space.
As gravitational forces act a new star is formed.
- What happens at the end of a
stars life depends on the size of
the star. When a star has used
up all the hydrogen 'fuel' in its
core, the core contracts and no
more energy is produced
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