Stars

Stars Our Sun is one type of star Our Sun is one type of star Create their own light Create their own light Nuclear fusion generates energy Nuclear fusion generates energy Atoms slam into each other at high temperatures and velocities to form larger heavier atoms Atoms slam into each other at high temperatures and velocities to form larger heavier atoms Classified based on: Classified based on: size size brightness brightness temperature temperature luminosity (brightness) luminosity (brightness)

Our Sun ●Our Sun is merely a spec in the Milky Way ●the Sun and Earth are located ½+ away from center in one of the spiral arms ●Sun orbits Milky Way at about 235 km/s around the center of the galaxy You are here!

Stars Types protostar protostar main sequence main sequence dwarf dwarf giant giant super giant super giant neutron neutronColors blue blue blue-white blue-white white yellow yellow red-orange red-orange red red

Magnitudes of Stars use telescopes to observe and measure light from stars use telescopes to observe and measure light from stars magnitude = brightness of a star magnitude = brightness of a star absolute – a measure of the light given off by a star absolute – a measure of the light given off by a star apparent – a measure of the amount of light received on Earth from a star apparent – a measure of the amount of light received on Earth from a star

Stars: HR Diagram Hertzsprung-Russell diagram organizes stars by temperature, brightness and groups by color and type Hertzsprung-Russell diagram organizes stars by temperature, brightness and groups by color and type “X-axis” = star temperature (reversed) “Y-axis” = absolute magnitude (brightness) Star Types are grouped together

Stars: Life Cycle—small star (Sun) 1. nebula = large area of gas & dust where stars are born (Protostar) 2. main sequence = stable, longest stage 3. red giant = star grows, but cools 4. white dwarf = star shrinks (moon size), but heats up; dying process 5. black dwarf = dead star

Stars: Life Cycle—massive star 1. nebula = large area of gas & dust where stars are born (Protostar) 2. main sequence = stable, longest stage 3. red supergiant = star grows, but cools 4. supernova = star blows off outer portion of gasses 5. neutron star = very small, massive, hot star

Stars: Life Cycle—VERY massive star 1. nebula = large area of gas & dust where stars are born (Protostar) 2. main sequence = stable, longest stage 3. red supergiant = star grows, but cools 4. supernova = star blows off outer portion of gasses 5. black hole = so small and dense, that even light cannot escape its gravitational pull

Life Cycle of a Star

Let’s Check… 1. Stars are classified by 4 major things: What are they? 2. What graphic do we use to compare stars? 3. The 6 major colors of stars are _?_. 4. Will our Sun go supernova? Why or why not?