An Intro To Our Galaxy

Question 1

Formation of a star

Answer 1

-10 million years
- space has some gases and dust in it
- over millions of years, gravitational forces between the dust and gas result in nebula, large highly compressed clouds

Question 2

Stable phase of a star

Answer 2

• called main sequence
• gravity created heat and pressure to fuel fusion reactions
• larger stars have shorter life spans
  Fg big - pressure big - more heat - rapid fusion reactions - run out of fuel

Question 3

Low mass star

Answer 3

( up to 1.5x sun)
- become white dwarf (our sun becomes this)
- a stable star with no fuel that radiates left over heat (dim star)

Question 4

Death of a star

Answer 4

• run out of hydrogen their main fuel
• gravity causes core to collapse
• heat is generated causing expansion of outer core
• expansion leads to cooling
• the cooler larger star is called a red giant

Question 5

Intermediate mass star

Answer 5

(1.5-3x sun)
- massive short lived explosion called a supernova
- blows away outer layer of star
- neutron star results ( pulsar is one star that spins and emits radio waves as pulses)

Question 6

High mass star

Answer 6

( 8x sun)
- supernova results in a black hole, an area so dense with such strong gravity not even light can escape

Question 7

Colours of hot and cold stars

Answer 7

Red- coolest with wavelengths in the IR
Yellow- stars like our sun are warmer with wavelengths in the middle to end of visible light
White- are even hotter with wavelengths just outside the ultraviolet end of the EMR spectrum
Blueish-white- hottest star- emits radiation mostly as visible light