Can somebody PLEASE help me with this?!?!?

Question

Okay...I have to complete this concept map that shows the evolution of a main sequence star with a mass similar to that of the Sun. It has to be 5 steps long, and I know the second step is that the main sequence star fuses hydrogen, and that the fourth sequence is that the giant fuses helium in its core. Please help!

Answer 1

Visit this link:
http://en.wikipedia.org/wiki/Stellar_evolution

It has excellent graphics and a comprehensive description of what you need...

Hope this helps,

JT

Answer 2

1. Protostar is formed from spinning cloud of gas which lights up when the temperature reaches 15 million degrees celsius. It heats due to the collisions of hydrogen as gravity pulls the gas together.
2. Hydrogen is changed to helium by nuclear fusion in the star's core.
3. When hydrogen is changed to helium the core shrinks, but the outer layer is still hydrogen. The core heats up, but the shell cools to a red color and expands...a red giant.
4. The core changed the helium to carbon, and the outside shell uses up the left over helium. The last of the hydrogen drifts away and forms a ring called the planetary nebula (nothing to do with planets).
5. The last of the helium is fused into carbon in the core. Nuclear fusion dies out and the star cools. Gravity causes the last of the star's matter to collapse inward. It shines a hot white. The star has become a tiny white dwarf. One teaspoon of a white dwarf weighs the same as several tons.

Answer 3

1) Gas and dust collapses onto itself, becomes a protostar (heat generated by gravitational energy and friction) and continues to collapse until somewhere in the centre, pressure and temperature are sufficient for hydrogen fusion.

2) When that happens, stars becomes a ZAMS (Zero Age Main Sequence). It then lives over 10 billion years on the Main sequence, happily fusing hydrogen.

3) Fusion in the centre is no longer possible (not enough hydrogen, too much Helium "ash" in the way); fusion begins in layers moving away from the core. The stars expands and cools: Red Giant. With time, Helium from outer layer fusion "falls" to the core (which has cooled). Pressure increases dramatically.

4) Helium fusion begins. Star now belongs to the "horizontal branch" on the H-R diagram (well above the Main sequence). With time, Helium runs low.

5) With the mass of the Sun, not enough pressure to trigger further fusion of heavier elements. Stars settles to become a white dwarf.

Answer 4

The fifth step: The power of the fusion, as heavier and heavier elements are burnt, can no longer balance the force of gravity due to the star's mass. The star collapses. In the case of a sun sized star the result would be a white dwarf. In more massive stars you end up with neutron stars or even black holes.

Answer 5

i wish i cood help but i cant soz