Topic 5: Unit-1 Flashcards
BIRTH, LIFE AND DEATH OF STARS -- Birth (8 cards)
What is a star?
A star is a luminous spheroid of plasma held together by self-gravity.
How does a star form from a nebula?
Gravity causes parts of the nebula to collapse and clump together, increasing in temperature and pressure to eventually form a protostar.
What is a nebula?
A nebula is a giant cloud of gas and dust in space, primarily made of hydrogen and helium, where stars are born.
What is a protostar?
A protostar is an early stage of a star’s formation, where gas and dust continue collapsing under gravity, but nuclear fusion hasn’t started yet.
What is a nuclear fusion?
A nuclear fusion involves the joining of two nuclei atoms to form a heavier nucleus and releases energy in the form of heat and light
When does a protostar become a main sequence star?
A protostar becomes a main sequence star when its core gets hot enough to start nuclear fusion, converting hydrogen into helium and releasing energy.
What is a nuclear fission?
A nuclear fusion is when nuclei of atoms are split apart to release energy
What role does nuclear fusion play in a star’s birth?
Nuclear fusion generates the energy that powers the star and counters the inward pull of gravity, allowing the star to stabilize and shine.
