11.1 - STARS – PART 1(Origins & Lifecycle)

By: Cassidy & Ekam

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)

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.

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 Sun

Close up stars

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

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)

THE BIRTH OF A STAR. (Con…)

• 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

Stars (All 3 pictures)

THE BIRTH OF A STAR

THE BIRTH OF A STAR. (Con…)

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)

Tiny Red Dwarf Star

Sun

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

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

Evolution Of A Star.

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.

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?

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. 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.

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.

Bibliography.

http://imagine.gsfc.nasa.gov/docs/science/know_l2/stars.html

http://www.oarval.org/star.htm

http://library.thinkquest.org/21008/data/star/birth.htm

http://www.universetoday.com/25331/size-of-stars/

http://www.google.ca/imghp?hl=en&tab=wi

http://aspire.cosmic-ray.org/labs/star_life/starlife_end.html

http://www.youtube.com/watch?v=uCz-uXRf4rA

BC Science 9 – McGraw-Hill Ryerson Text Book