Transcript Life Cycle of a Star

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 fusion
What 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
Hertzsprung-Russell (HR) Diagram
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 Giants
After 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