Discuss the source of energy for a star like the Sun when it is ...

[acc299]

Discuss the source of energy for a star like the Sun when it is on the Main Sequence. Include the role of nuclear, electrical, and gravitational forces, temperature, and chemical composition.
 
  How long can this star burn its fuel and what marks the end of this stage of its life?

Question 2

What is the closest that extrasolar planets have been found to their stars?
 
  A) nearer to their stars than Earth to the Sun
  B) nearer to their stars than Saturn to the Sun
  C) nearer to their stars than Mercury to our Sun
  D) unknown: we do not know the distance with enough accuracy to say

[jlaineee]

Answer to Question 1

The Sun produces energy via the proton-proton cycle of nuclear fusion. The gravity of the Sun has compressed the hydrogen of the Sun to the point where it has heated to 15 million K, hot enough so that the protons can overcome their electromagnetic repulsion. As the Sun burns, helium ash builds up in the core. This goes on for around 10 billion years. The Sun's main sequence stage ends when the helium ignites and fuses to become carbon.

Answer to Question 2

C

[acc299]

Both answers were spot on, thank you once again

[jlaineee]

Great! Please up vote