Final answer:
The luminosity of a star is affected by its surface area, energy flux, and mass.
Step-by-step explanation:
The luminosity of a star is affected by several factors, including its surface area and energy flux. The luminosity (L) of a star is given by its surface area in square meters times the energy flux: L = (A×F).
Another factor that affects the luminosity of a star is its mass. It's a reasonably good approximation to say that luminosity varies as the fourth power of the star's mass. If two stars differ in mass by a factor of 2, then the more massive one will be approximately 16 times brighter; if one star is 1/3 the mass of another, it will be approximately 81 times less luminous.
Therefore, the surface area, energy flux, and mass are all factors that affect the luminosity of a star.