PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
Earth’s mean surface temperature is approximately T⊕=288K, and satellite measurements show that Earth’s emitted spectrum peaks at λpeak,⊕=10μm. An exoplanet is discovered orbiting a distant star. Infrared observations record the exoplanet’s peak emission wavelength as λpeak,exo=17μm. Assume both planets radiate as perfect blackbodies.
(a) Estimate the exoplanet’s mean surface temperature Texo. Show your reasoning.
(b) Calculate the ratio of the exoplanet’s emitted power per unit area to that of Earth. Identify the physical relationship you apply in this calculation.
(c) Suppose follow-up data indicate the exoplanet receives the same average stellar flux per unit area that Earth receives from the Sun. Discuss two possible physical explanations for the difference between the equilibrium temperatures of the two planets.