1. White Dwarf

2. Collapse The core of a giant star collapses as helium fuses. –Outer layers continue to expand –Loses over half its mass The lost mass comes off in helium flash explosions. core outer layers of gas

3. Planetary Nebulae Ejected gas from a star is lit up by the shrinking core. –Round shape –Glows with colors seen from planets The gas is called a planetary nebula. –Not really part of a planet

4. Degenerate Matter After explosions the remaining core collapses due to gravity. –Radiation too weak At high density, the electromagnetic force between electrons holds the material of the core apart. This compressed material is degenerate matter. –Core of giant stars –Sun mass in Earth size

5. Fate of the Sun The Sun will collapse after millions of years as a giant. –Heat to class A or B –Shrink to Earth size The end of the sun will be a small, hot star that will last until the remaining material burns up. Sun

6. Bipolar Nebulae Planetary nebulae can have multiple flashes. –Ring of ejected matter around the core –Later flashes blocked by ring The gas goes in the remaining two directions forming a dumbbell or hourglass shape.

7. Bare Core Stars less than 8 M  will all end by helium flashes as gas is ejected. The remaining core is called a white dwarf. The white dwarf will cool over billions of years until it is black.