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Life Cycle of a Star. A journey through it’s birth ‘til it’s death. By Anna, Damon, Shannon, Jon, and Patricia. Objectives. How stars are formed What they are made up of What happens in the middle of life Death of stars of different sizes. Birth of a Star. Enormous clouds of gas and dust
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Life Cycle of a Star A journey through it’s birth ‘til it’s death. By Anna, Damon, Shannon, Jon, and Patricia
Objectives • How stars are formed • What they are made up of • What happens in the middle of life • Death of stars of different sizes
Birth of a Star • Enormous clouds of gas and dust • Gravity tries to pull the materials together • A giant ball forms • Center of ball reaches 15 million degrees
Nuclear fusionWhat is it? • Enormous pressure at center of ball • A plasma is created • Nuclei crash together, then fuse
Midlife of a Star • Goal is to reach equilibrium • Main Sequence: 1. Basic Reactions 2. Hydrostatic equilibrium 3. Transport of energy
Death of a Star (depending on the mass of the star) • Sun-like stars (mass under 1.5 times the mass of the Sun) • Huge Stars (mass between 1.5 and 3 times the mass of the sun) • Giant Stars (mass over 3 times the mass of the Sun)
Sun like stars (mass under 1.5 times the mass of the sun.) • Become Red GiantsAfter exhausting their hydrogen they burn Helium • Outer Layers Ejected to Planetary Nebula • Leaving a dense white dwarf
White Dwarf 1.4 • No fuel left to burn • Radiates remaining Heat • Eventually becomes a Black Dwarf if nothing else effects star
Red Super Giant • Rare due to short life span • 2000 known in galaxy • Made up of Helium, Hydrogen, and carbon • 8-10 times more massive then sun • Extremely bright for hundred thousand to a million years • Implodes on itself ending in a type II supernova
Supernova • Explosion of a star in space • Occurs when nuclear fuel is exhausted • No longer supported by release of nuclear energy • A rare event in our galaxy (last being seen in 1604) • Remnants can be seen for several weeks • Supernova end phase is a neutron star
Neutron Star • Final stage in death of a star • May appear in supernova remnants, as isolated objects or in binary systems • About 20km and 1.4 times more massive then our sun • Posses gravitational field about 2 x 10^11 that of earth • Escape velocity is about half the speed of light • Are electrically neutral
Death of Huge stars (mass between 1.5 to 3 times that of our sun)
Giant Stars (mass over 3 times the mass of the sun.) • Red Super Giants • Supernova • Black holes
Summery • Stars are made up of interstellar gasses, dust and gravity • The goal of a star is to reach an equilibrium • What a star turns into when it dies depends on the size of the star whether it is smaller then our sun, the same size or larger then our sun