How does the luminosity of a star compare to the energy being produced in the co

Question

How does the luminosity of a star compare to the energy being produced in the core each second if the star is a main sequence star? There is no strong relationship. For the Sun the luminosity is equal to the energy produced each second in the core. But for many main-sequence stars the luminosity only depends on the mass of the star. It has no relationship to the reaction rate in the core. The luminosity is lower than the energy being produced in the core each second. This is because the energy produced in the core leaves the core and then supplies the kinetic energy to the gas molecules in the outer layers of the star. Then the left over energy comes out as luminosity. The luminosity is higher than the energy being produced in the core each second. This is because the gas in a star is hot. So energy is being produced but the gas molecules already have a lot of kinetic energy of their own. When the gas kinetic energy is added to the energy being produced in the core, the total is the luminosity of the star. The luminosity is equal to the energy being produced in the core each second. This is because the core produces energy which heats up the gas in the outer layers of the star. But the gas particles also lose their kinetic energy to radiant energy. The result is an equilibrium, where the energy production equals the energy lost through radiation.

Explanation / Answer

Luminosity is defined as the total energy that is emitted by a star per second. Now the amount of energy emitted by the star per second is equal to that produced in its core per second if we assume that the star is not expanding or contracting, that is it is in equilibrium.

So the correct option is the last option.

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