1. Intrinsic Luminosity: This refers to the actual amount of light a star emits. Stars come in different sizes and temperatures, and hotter, larger stars are intrinsically brighter than cooler, smaller ones.
2. Distance: The farther away a star is, the dimmer it appears. This is because light spreads out as it travels, so the same amount of light from a distant star is spread over a much larger area when it reaches Earth.
3. Interstellar Extinction: Dust and gas clouds in space can absorb and scatter starlight, making stars appear fainter than they actually are. This effect is more pronounced for stars that are located behind denser clouds.
