Describe different types of stars. What is a supernova? Do all stars end this way? Check Missing Assignments

LIFE CYCLE OF STARS

Light year Distance that light travels in one year 1 light year = 9.46 trillion kilometers (5.87 trillion miles) Speed of light = 300,000 km/second (186,000 miles/second)

The Beginning Nebula – Large cloud of dust and gas in space – Star nursery Gravity pulls gases together to begin nuclear fusion and a star is born

Classified Size Mass Brightness Color Temperature Age Classification can change as it ages

Main-Sequence Star 2 nd and longest stage of stars life cycle As long as nuclear fusion continues, the star will continue to shine

Giants and Supergiants Most stars, 3 rd stage of life cycle Core shrinks Atmosphere becomes very large and cools Creates red giants and supergiants – Red giant: 10x bigger than Sun – Red Supergiant: 100x bigger than Sun

White Dwarf Final stage of star’s life cycle Small, hot, dim star that is the leftover center of an old star Will eventually “burn” out billions of years later

Death of Bigger Stars Supernova – gigantic explosion in which a massive star collapses and throws its outer layers into space Neutron star – Star collapses where electrons and protons smash together to create neutrons Pulsar – If a neutron star is spinning it emits rapid pulses of radio and light waves

Death of a Bigger Stars (continued) Black hole – A star that is so massive that when it explodes it is so dense that even light cannot escape its gravity

Describe different types of stars. Are there more white dwarfs or black holes in the universe?