ABSTRACT
In this chapter, we focus primarily on how we detect planets around stars other than the Sun—commonly known as extrasolar planets, or exoplanets—and what we can currently determine about these planets’ properties and characteristics. We will consider the various detection methods, in particular indirect methods that find these planets through their influence on their parent star. We will also consider the direct detection of exoplanets, as this is becoming a successful method and will ultimately play a key role in determining their atmospheric properties. We will consider what would be required for a planet to have liquid water on its surface, thought to be important for habitability, and will discuss the known planets for which this might be the case. Determining if a planet is indeed potentially habitable will require characterizing its atmosphere, so we will discuss what we currently know about exoplanet atmospheres and what we might uncover in the coming years and decades.
