Background
The appearance of extrasolar planets is largely unknown because of the difficulty in making direct observations of extrasolar planets. In addition, analogies with planets in the Solar System can apply for few of the extrasolar planets known; because most are wholly unlike any of our planets, for example the hot Jupiters.
Bodies which transit their star may be spectrographically mapped, for instance HD 189733 b. That planet has further been shown to be blue with an albedo greater (brighter) than 0.14. Most transiting planets are hot Jupiters.
Speculation on the appearances of unseen extrasolar planets currently relies upon computational models of the likely atmosphere of such a planet, for instance how the atmospheric temperature–pressure profile and composition would respond to varying degrees of insolation.
Read more about this topic: Sudarsky Extrasolar Planet Classification
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