Unit E – Space Exploration The Distribution of Matter in Space Lesson 4-2: (Sec 1.3) The Distribution of Matter in Space

A. Stars a is a hot, glowing ball of gas (mainly hydrogen but also helium) star stars vary in colour, size and density stars are , stars are hot blue Cooler red a shows that stars fall into Hertzsprung-Russell Diagram distinct groupings slide 1 of 6

Hertzsprung-Russell Diagram Sun slide 2 of 6

B. Birth of a Star a is an accumulation of gas and dust nebula steps in birth: 1. swirling dust, gas collapse under gravity 2. core mass and temperature increase 3. core of material glows, forming a protostar 4. when the core temperature reaches 10 million degrees C, fusion begins and a star is born slide 3 of 6

C. Life & Death of a Star the determines the type of star mass of a star most stars start out in the main sequence the depends on the mass of the star life cycle slide 4 of 6

sun-like stars red giant white dwarf black dwarf nebula main sequence star neutron star (pulsar) massive stars red supergiant supernova black hole slide 5 of 6

D. Galaxies a is a grouping of millions or billions of stars, gas and dust held together by gravity galaxy can be spiral shaped (Milky Way), elliptical, or irregular slide 6 of 6

Assignment Worksheet 3