3-10 Stars

As stars get older they go through changes.  A star begins "old age" when its central core of hydrogen has become all helium.  Its source of energy is gone.  The outer layers of the star begin to expand and cool down.  It is a dull red in color.  It is known as a red giant.

The outer layer forms a ring nebula.  (Remember a nebula is a swirling cloud of dust and gas.)  This nebula disappears into space leaving behind the core.  The core becomes hotter and hotter as it collapses and forms a small, white star.  This is called a white dwarf.

The white dwarf has no energy left at this time.  Because of this it grows dimmer and dimmer until it is a cold, black sphere called a black dwarf.

People grow older over a period of months and years.  You can't see the changes in stars because star changes occur over millions and sometimes billions of years.

Directions: Answer the questions about how a star dies.

A star begins "old age" when its central core of becomes all helium.

When the outer layers of the star begin to expand and cool and it is red in color, it is known as a red .

A is a swirling cloud of dust and gas.

The collapsed core forms a small, white star.  This is called a white .

With no energy the left a star grows dimmer and dimmer until it is a cold, black sphere called a black .

Star changes occur over and sometimes of years.

Star death occurs in stages.  Put the following in order.  Use the numbers 1, 2, and 3.

White Dwarf

Red Giant

Black Dwarf