Stars Flashcards
1
Q
What are Stars?
A
- Stars are hot, glowing spheres of gas
- They differ in their luminosity (or brightness), temperature, composition, mass, and size
- The bigger a star is, the hotter it becomes and the faster it burns through its fuel.
2
Q
What are the stages of the life cycle of a star (1st way)?
A
- Stellar Nebula
- Average Star
- Red Giant
Planetary Nebula - White Dwarf
3
Q
What is a Stellar Nebula?
A
- The birthplace of stars
- Giant gas clouds filled mostly hydrogen gas
- Gravity pulls hydrogen atoms together, and as the gravitational force becomes stronger, the hydrogen atoms fuse into helium through nuclear fusion, releasing energy. The size and color of a star depend on the initial amount of hydrogen it has.
4
Q
What is an Average Star?
A
- An average star is a star that is typical in size, temperature, and brightness.
- The Sun is an example of an average star.
- An average a star remains stable due to a constant tug-of-war between two forces. The energy released by nuclear fusion creates an outward force, while gravity pulls inward. These opposing forces balance each other, keeping the star stable.
5
Q
What is a Red Giant?
A
- As an average star runs out of fuel, it expands into a red giant, becoming hundreds of times larger than its original size.
- In about 5-6 billion years, the Sun will expand enough to reach Earth’s orbit.
6
Q
What is a Planetary Nebula?
A
- A red giant that becomes unstable and disintegrates
- Gravity will maintain a small core but most of the gas layers will be blown into space
7
Q
What is a White Dwarf?
A
- The leftover core of the red giant (not blown into space) is the white dwarf
- Very dense
- Mostly made of carbon and oxygen
- Continues to produce light as it cools
8
Q
What are the stages of a the life cycle of a star (2nd way)?
A
- Stellar Nebula
- Massive Star
- Red Super Giant
- Supernova
- Neutron Star or Black Hole
9
Q
What is a Massive Star?
A
- Much larger than the sun
- Burn hydrogen quicker than an average star
- Hotter, blue colour
- Shorter lifespan than average star
10
Q
What is a Red Super Giant?
A
- When a massive star runs out of fuel it will become a red supergiant so large they are able to store heavy elements like magnesium, titanium and iron in their cores
11
Q
What is a Supernova?
A
- After being a red supergiant a violent explosion called a supernova
- It occurs as elements in core collapse because of gravity and rebound producing the explosion
12
Q
What is a Neutron Star?
A
- After the supernova a neutron star will remain
- Gravity so strong that is makes electrons and protons combine to make neutrons
- Very very dense
13
Q
What is a Black Hole?
A
- If a red supergiant is big enough, the remainders from the supernova will WARP space and time
- Gravity so strong that nothing not even light can escape
- A void in space
14
Q
What does the brightness of a star indicate?
A
Brightness of a star depends on its size, luminosity and distance from Earth
15
Q
What is luminosity?
A
Luminosity: amount of energy a star radiates per second
