1. Temperature: A star's temperature dictates how much energy it radiates per unit area. Hotter stars emit more energy in the form of light, making them appear brighter.
2. Size (or Radius): The larger a star's surface area, the more energy it can radiate overall. A bigger star, even at the same temperature, will be more luminous.
These two factors are tightly interconnected. A star's temperature is determined by its internal processes, including nuclear fusion, while its size is influenced by factors like its mass and evolutionary stage.
