Table 2.

Desirable “Internal” General Properties of an Atmosphere and Surface to Know About a Potentially Habitable Exoplanet

Climatic and surface properties	Atmospheric properties
Average surface emission temperature, Tsurfe	Bulk composition and redox state
Bond albedo, AB	Surface barometric pressure
Effective temperature, Teff	Clouds or haze composition and structure
Composition of the surface phase:	Vertical structure
Liquid water or ice	Mixing ratios of key trace species:
Silicates	H2O from evaporation
	Volcanic gases (e.g., SO2 or H2S)
	Greenhouse gases (see Table 3)