1. 11.1 - STARS – PART 1 (Origins & Lifecycle)
By: Cassidy & Ekam

2. WHAT IS A STAR? A star is an object from space
Made up of hot gases and dust
The core is like a thermonuclear reactor, (a nuclear reactor that uses controlled nuclear fusion to generate energy)

3. WHAT IS A STAR? (Con…)
9000 billion stars have formed over 13.7 billion years
Space is filled with interstellar matter, (matter occurring between the stars of our Galaxy) made up of gas
Far away stars.

4. WHAT IS A STAR? (Con…)
A luminous, (Glowing) sphere held together by gravity
The eye can only see 2000 stars in the sky at a time
There are stars hotter and cooler than the Sun
Close up stars
Sun

5. THE BIRTH OF A STAR.
Begins to form from materials in a nebula (cloud of dust) when gravity starts acting on chunks of dust and gas pulling them together
Star being born

6. THE BIRTH OF A STAR. (Con…)
Mass grows and material collapses on itself and contracts, (Shrink)
Early phase of a star: Protostar, (Proto means earliest)
If mass stays small, the protostar may shrink away never being a full star
Birth of Stars (Both)

7. THE BIRTH OF A STAR. (Con…)
Stars (All 3 pictures)
If a protostar collects enough mass of dust and gas, the core will reach about 10 million degrees celceuis
Atoms fuse, (Mix or Melt) together to create one large atom

8. THE BIRTH OF A STAR

9. THE BIRTH OF A STAR. (Con…)

10. STAR SIZES. The biggest star yet found is VY Canis Marjoris
The Sun is the average size of a star
The smallest stars are called tiny red dwarfs
VY Canis Marjoris (Above)
Sun
Tiny Red Dwarf Star

11. Star Sizes. (Con…)
A star needs as much as 7.5% mass of the sun for the star to be able to support nuclear fusion in its core
If it’s below this mass then you get a failed brown dwarf star
Star Sizes

12. Star Sizes. (Con..)
A red dwarf star known as Proxima Centauri is the closest star to the Earth
The Sun has a diameter of 1.4 million Km across
When the sun nears the end of its life it will bloat up as a red giant, and grow to 300 times its original size which will engulf Mercury, Venus and Earth
Proxima Centaui
Exploding Sun

13. Evolution Of A Star.

14. Why Are Stars So Important?
Stars are a part of the universe, mankind needs them
Stars like Supernovas are needed because the oxygen you breathe, carbon in your bones, and hydrogen in the water you drink all resulted from the death of a star
Supernovas (Both Pictures)
Supernova: A rare explosion of most of the material in a star, causing an extremely bright, short-lived object that emits large amounts of energy.

15. Review Questions.
1: In your own words, summarize what a star is. At least 4 sentences.
2: What are the first 3 main steps in the process of the birth of a star?
3: The term “Nebula” means _______ & _______. Answer:_______
a: Gas & Rocks b: Dust & Gas
c: Hydrogen & Iron d: Carbon & Iron
4: What is the name of the biggest star that has been found called?
5: Why are stars are needed in the universe?

16. Answer Key.
Answer Key.
1: A star is a luminous, (Glowing) sphere held together by gravity. The eye can only see 2000 stars in the sky at a time. The most common known star is the Sun billion stars have formed over 13.7 billion years. Space is filled with interstellar matter, (matter occurring between the stars of our Galaxy) made up of gas.
2: A star begins to form from materials in a nebula (cloud of dust) when gravity starts acting on chunks of dust and gas pulling them together.
Mass grows and material collapses on itself and contracts, (Shrink).
Atoms fuse, (Mix or Melt) together to create one large atom.
3: b: Dust & Gas.
4: The biggest star that has been found is called VY Canis Marjoris.
5: Stars are a part of the universe, mankind needs them. Stars like Supernovas, (Supernova: A rare explosion of most of the material in a star, causing an extremely bright, short-lived object that emits large amounts of energy) are needed because the oxygen you breathe, carbon in your bones, and hydrogen in the water you drink all resulted from the death of a star.

17. Bibliography.
BC Science 9 – McGraw-Hill Ryerson Text Book