105 - Stars

Question 1

What are the stages in the life of a large star?

Answer 1

Protostar -> main sequence -> red super giant -> supernova -> neutron star/black hole

Question 2

What are the stages in the life of a smaller star?

Answer 2

Protostar -> main sequence -> red giant -> white dwarf

Question 3

Is the sun a large star or a smaller star?

Answer 3

Smaller

Question 4

What is a protostar?

Answer 4

A cloud of dust and gas pulled together by gravity

Question 5

How is a main sequence star formed?

Answer 5

Gravitational energy -> heat energy

Hydrogen nuclei undergo fusion and form helium

Gives out heat and light

Question 6

What are the properties of a main sequence star?

Answer 6

Pressure from heat balances with inwards force of gravity

Stable for billions of years

Question 7

What happens when a star begins to run out of hydrogen?

Answer 7

Heavier elements are made by helium fusion

Star swells and becomes red as surface cools

Question 8

How is a planetary nebula produced?

Answer 8

A red giant expels its outer layers of dust and gas

Question 9

What is left when a star ejects its outer layer?

Answer 9

A white dwarf which cools down then disappears

Question 10

What happens after the red super giant stage?

Answer 10

Expand and contract as heavy elements are formed

Supernova explodes and forms new planets and stars

Question 11

What is left behind after a supernova?

Answer 11

A dense neutron star

A black hole in very large stars