Recently I been reading about exoplanets on wikipedia when I came across a line that caught my idea: So I started wondering exactly what did Wikipedia mean by "based on the intensity of light" and later on by "temperature measure by observing the variation in infrared radiation". I mean really how do astronomers and astrophysics find the temperatures of nearby exoplanets even though they are hundreds of parsecs away. Specifically, I really wanted to know the following two things: 1. Where kind I find more through information about theory and concepts behind the transit method of observing exoplanets? Specifically I was curious about the formulas/theory they used. 2. How does one estimate, say to the nearest hundred degrees, a exoplanet's effective temperature when the exoplanet's albedo is unknown?