Space Physics Flashcards
Life Cycle of Stars - Stage 1
A cloud of dust and gas (a nebula) is formed.
Life Cycle of Stars - Stage 2
The dust and gas are pulled together by gravity to form a protostar. Hydrogen nuclei undergo nuclear fusion to form helium nuclei due to a rise in temperature and density of the star. This gives out a huge amount of energy, which keeps the core of the star hot. A star is born.
Life Cycle of Stars - Stage 3
The star enters a long stable period in which the star is called a main sequence star (like The Sun).
Life Cycle of Stars - Stage 4
Eventually the hydrogen runs out. The star then swells into a red giant or a red super giant.
Life Cycle of Stars - Stage 5 (If red giant was formed)
A small-to-medium-sized star like the Sun then becomes unstable and ejects its outer layer of dust and gas. This leaves behind a hot, dense solid core - a white dwarf.
Life Cycle of Stars - Stage 6 (If red giant was formed)
As a white dwarf cools down, it emits less energy. When it no longer emits a significant amount, it is called a black dwarf.
Life Cycle of Stars - Stage 5 (If red super giant was formed)
Big stars undergo more fusion and expand and contract several times, forming elements as heavy as iron in various nuclear reactions. Eventually they’ll explode in a supernova, forming elements heavier than iron and ejecting them into the universe to form new planets and stars.
Life Cycle of Stars - Stage 6 (If red super giant was formed)
The exploding supernova throws out the er layers of dust and gas into space, leaving a very dense core (a neutron star). If the star is massive enough, it will become a black hole - a super dense point in space.
What is red-shift?
The wavelength of light is stretched, so the light is seen as ‘shifted’ towards the red part of the spectrum.
