Exoplanetology, or exoplanetary science, is an integrated field of astronomical science dedicated to the search and study of exoplanets (extrasolar planets). It employs an interdisciplinary approach which includes astrobiology, astrophysics, astronomy, astrochemistry, astrogeology, geochemistry, and planetary science.
The first exoplanet was detected on 6 October 1995, and was named 51 Pegasi b. When extrasolar planets are observed to transit their parent stars, astronomers are able to assess some physical properties of the planets from an interstellar distance, including planetary masses and size, which in turn provide fundamental constraints on models of their physical structure. Furthermore, such events afford the opportunity to study the dynamics and chemistry of their atmospheres.
Statistical surveys and individual characterization are the keys to addressing the fundamental questions in exoplanetology. Varying techniques have been used to discover 2,002 planets outside the Solar System. Documenting the properties of a large sample exoplanets at various ages, orbiting their parent stars of various types, will contribute to increased understanding —or better models— of planetary formation (accretion), geological evolution, orbit migration, and their potential habitability.