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Aditional Physics > Life Cycle Of A Star > Flashcards

Flashcards in Life Cycle Of A Star Deck (50):
1

Which two star stages follow the main sequence star?

Either red super giant or red giant

2

What is the sequence after red super giant?

Supernova --> neutron star -or-> black hole

3

What is the sequence after red giant?

White dwarf

4

What are the first two stages of the cycle?

Protostar --> main sequence star

5

State the sequence in terms of a star bigger than the sun.

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

6

State the sequence in terms of a sun like star.

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

7

Neutron star or...

Black hole

8

Clouds of dust and gas are called...

Nebula

9

What force and what does it do to the star (protostar)?

Gravity pulls more material into the star which is in the form of a nebula.

10

What happens when gravity pulls more material into the protostar?

Compresses.

11

What happens to the protostar when it's compressed?

Starts warming up.

12

After the protostar stage, what does the gravitational energy transfer into?

Heat energy

13

What process is allowed by heat energy in main sequence stage?

Fusion

14

Main sequence stage- fusion of what into what?

Hydrogen nuclei --> helium

15

What happens after nuclear fusion starts to the main sequence star?

Star enters stable period.

16

What does nuclear fusion produce in the main sequence star to allow it to enter a stable period?

Heat

17

How does heat allow the stable period in a main sequence star?

Heat produced causes an increase of outwards pressure because of the increased motion of particles inside the star.

18

Explain the stable period in a main sequence star.

Heat produced by nuclear fusion cause increase of outwards pressure in the star...
Gravitational forces are still trying to collapse the star in on itself...
THESE BALANCE EACH OTHER OUT.

19

How long does the main sequence star maintain its energy output in the stable period?

Millions of years. Due to massive amounts of hydrogen it consumes.

20

What is the first step as a main sequence star starts to turn into a red (or super) giant?

Hydrogen begins to run out

21

When hydrogen runs out in the process of a main sequence star turning into a red or super giant, what does this cause?

Nuclear fusion of HELIUM starts creating heavier elements like iron.

22

What happens to a star to make it into a giant?

It swells

23

What happens as the surface of a giant/super giant cools?

It turns red

24

What process is going on with what elements in a red giant?

Fusion of nuclei with elements other than hydrogen and helium.

25

What happens to a red giant when fusion stops?

Comes to an end.
No more heat --> no more outwards pressure

26

What does a lack of outwards pressure mean for a red giant?

Gravity causes the core to collapse in on itself.

27

Size of red giant.....

Can reach Venus's orbit.

28

Explain planetary nebula.

As star collapses, it ejects it's outer layer of dust and gas as planetary nebula.

29

How does the ejection of planetary nebula leave a white dwarf?

It leaves behind a hot dense solid core.

30

What is a white dwarf?

A small dim star

31

What are the atoms like in a white dwarf?

Densely packed.

32

How greater is the gravity of a white dwarf to the Earth?

100 000 times greater

33

What happens after a white dwarf cools?

It becomes a black dwarf.

34

How long does it take a white dwarf to transform into a black dwarf?

Billions of years

35

What happens to black dwarf stars?

Eventually disappear

36

How big can the red super giant swell to?

The orbit of Jupiter.

37

To go through the red super giant stage, how big does the star have to be?

1.5 of the sun

38

What is a supernova?

The event of a red super giant exploding.

39

Before a supernova, the fusion of heavy nuclei results in what?

The formation of heavy elements like iron.

40

What does fusion before a supernova allow?

The star to glow brightly.

41

What happens to the star before the supernova?

Expands and contracts several times.

42

Ho much energy can a supernova release?

As much energy in a few years as the sun will release in it's entire 10 billion years.

43

Why do supernova explosions happen?

Due to gravity collapsing the star on itself.

44

How heavy are the elements that are formed during a supernova and what happens to them?

Heavier than iron. Ejected into space.

45

What is a neutron star?

The very dense core left after a supernova.

46

How big in relation to the sun is a neutron star?

Up to 3 times bigger.

47

How dense is a neutron star?

The size of the earth and a mass greater than the sun.

48

How big must a star be to qualify as a black hole?

3 times bigger than the sun.

49

What is a black hole?

A small ball of matter which is even denser than a neutron star.

50

Explain how big gravity is on a black hole.

Not even light can escape it.