ABSTRACT
Solar planets are clearly distinguishable as terrestrial and giant planets. While telluric planets have rocky cores and a solid crust, the giant gas planets are rich with primordial hydrogen and helium and are incapable of supporting life since they lack a solid crust. Internal structure and atmospheric composition of an exoplanet plays an important role in understanding if it is habitable or not. Any habitable exoplanet should basically be terrestrial in nature. This chapter lists out other essential characteristics of a habitable planet. A study of the atmosphere of an exoplanet provides insights into its evolutionary history. This chapter also deals with the several ground and space-based technical facilities available for observing and analyzing a planet’s atmosphere. Atmosphere of an exoplanet is in a state of dynamic circulation which decides thermal distribution across its surface and has a direct bearing on its habitability.
