The Runaway Greenhouse Effect on Hycean Worlds

Journal article

The discovery of over 5700 exoplanets has led to a boom in the field of exoplanet demographics over the past decade. Led by swaths of exoplanet discoveries from NASA\u27s Kepler space mission, astronomers have been conducting statistical studies of the exoplanet population in search of trends in various planetary and host stellar parameters. These investigations are informing our understanding of how planets form and evolve, thus putting our solar system into a galactic context. In this chapter, we review many of the major features uncovered in the distributions of physical and orbital parameters of known exoplanets including the Radius Valley, the Neptunian Desert, the Peas in a Pod pattern, dynamical properties that point toward likely formation/migration mechanisms, as well as trends with host stellar parameters such as the time-evolution of exoplanetary systems and the search for planets within the Habitable Zone. The overarching theme is that exoplanetary systems exhibit an incredible diversity of planet properties and system architectures that do not exist within our own solar system. A promising future awaits the field of exoplanet demographics with increasingly deep investigations planned following the launch of numerous dedicated space telescopes over the coming years and decades.Preprint of a chapter for the \u27Encyclopedia of Astrophysics\u27 (Editor-in-Chief Ilya Mandel, Section Editor Dimitri Veras) to be published by Elsevier as a Reference Module. 18 pages, 10 figure

Authors: Innes, H; Tsai, S-M; Pierrehumbert, RT

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Astronomical Society
• Journal: The Astrophysical Journal
• Volume: 953
• Issue: 2
• Pages: 168-168
• Publication date: 2023-08-16
• DOI: 10.3847/1538-4357/ace346
• EISSN: 1538-4357
• ISSN: 0004-637X
• Language: English
• Keywords: Astronomy; Atmospheric sciences; Convection; Radiative equilibrium; Atmosphere (unit); Exoplanet; Astrophysics; Physics; Radiative transfer; Water vapor; Circumstellar habitable zone; Optics; Meteorology; Planet; Astrobiology