Life Cycle of Stars Flashcards
What do stars initially form as?
Nebulas- a cloud of gas and dust.
How does gas and dust spiral together?
The force of gravity.
What does the force of gravity do to a nebula?
Pull together the gas and dust.
What causes the temperature of a nebula to rise?
Gravitational energy being converted into heat energy
When the temperature gets high enough, what happens to the hydrogen nuclei?
it undergoes thermonuclear fusion to form helium nuclei and gives out massive amounts of energy.
How is a star born?
- the force of gravity creates a nebula by pulling
together the dust and gas
*gravitational energy is converted to heat energy
*when temperature rises enough, hydrogen nuclei undergo thermonuclear fusions to form a helium nuclei and give out massive amounts of energy.
When a star is born, what does it immediately enter?
it enters a long stable period where the hear created by nuclear fusion provides an outward pressure to balance the force of gravity pulling everything inwards.
What is a star called when it enters a long stable period and how long does it last?
Called a main sequence star and this period can last several billion years.
In the core of a star what eventually runs out?
Hydrogen
What happens when the hydrogen in the core of a star begins to run out?
the star swells into a red giant
why does a red giant star become red?
because the surface cools
how does a red giant star form?
when a main sequence star eventually begins to run out of hydrogen in the core, it swells into a red giant
is the sun classified as a big or small star?
small
after becoming a red giant star, what kind of star does it become?
planetary nebula and white dwarf
how does a red giant become a planetary nebula?
it becomes unstable and ejects layers of dust and gas as a planetary nebula
