Nuclear Fusion in stars is controlled by the dependence of density and mass? True or False?

Question

Cant find this in my Astronomy book. Please help

Answer 1

Nuclear fusion in stars is controlled by temperature. In the case of our sun, it's another way of saying how fast protons move around in the core. The more gravitational pressure on the core, the faster those little suckers move around. If the gravitational pressure is sufficient, the protons in the core of the star are zipping along so fast that the temperature goes to around 10 million Kelvin (10 million degrees above absolute zero). That's where something interesting happens. The protons get close enough to one another to overcome the strong nuclear force (the positive charge) that normally keeps protons apart. The protons fuse together in the high energy collisions, emitting gamma rays and neutrinos in the process. That's your nuclear fusion. Lots of high energy gamma rays pushing outward from the core, holding the inward gravitational pressure in equilibrium. If the core runs out of hydrogen to fuse, it shuts off. Nuclear fusion stops. The temperature goes down. This causes the sun's mass to to start weighing down on the core again, there's nothing to hold up the star from further collapse. Eventually, the temperature in the core again starts to go up because of the increasing inward pressure. If the now-helium core can get to 100 million degrees Kelvin, helium fusion is possible, and once again the star is held up by the outward pressure of the helium fusion. Temperature controls. But mass/density and the force of gravity make it happen in the first place.

Answer 2

Nuclear fusion in stars is caused by the inward pull of gravity and the outward push of the energy produced by the fusion. In the different life stages of the star these two things constantly battle to maintain a balance.

Answer 3

Your question is non-sequitor.

As gas compresses, it heats up and gets denser. At some point the heat is enough to engage fusion. A star is born. Fusion isn't so much controlled as it just happens. The gas mixture and total mass are the most basic variables for fusion.

If you re-word the question, you will get better answers. Try again!

Answer 4

Sounds like this is one of "those" questions-the ones which are asked and seem to make little sense. It seems well explained above and I'd agree but I'm not an astronomer.

Look in your notes or ask someone who remembers very well what happens in class, maybe the professor worded something similarly that can point to towards what the real intention of the question is.