Stellar Birth

Jade J

Rachael H

Stages of Stars

• In the birth of a star there are seven stages in it’s formation.

• A star's life is a constant battle against gravity, and pressure support. That battle begins as soon as a molecular cloud begins to collapse into a protostar.

Interstellar Clouds

• Name given to an accumulation of gas, plasma and dust.

• Denser than the average region of interstellar medium.

Collapsing Cloud Fragment

• At this phase the cloud is very diffuse, so heat is not trapped so the temperature does not build up.

Fragmenting Ceases

• Several tens of thousands of years after the collapse of the cloud the center becomes opaque and the temperature rises greatly.

• The cloud typically begins to shrink in size and the appearance of a potostar can be seen at the center.

Protostar

• At this stage the cloud begins to collapse on its self increasing the temperature and causing it to contract.

Protostar Evolution

• As the protostar moves past stage four it moves closer to the main sequence.

• This stage is characterized by violent surface activity and strong protostellar winds.

Newborn Star

• The temperature has now become high enough for thermonecular fusion to begin

• This results in somewhat lower luminosity

Main Sequence

• The star contracts a bit more and enters into hydrostatic equilibrium.

• During the main sequence lifetime, the star achieves stability by gas pressure.