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artist rendering of a habitable planet landscape

What makes a planet habitable?

A planet’s habitability, or ability to harbor life, results from a complex network of interactions between the planet itself, the system it’s a part of, and the star it orbits. The standard definition for a habitable planet is one that can sustain life for a significant period of time. As far as researchers know, this requires a planet to have liquid water. To detect this water from space, it must be on the planet’s surface. The region around a star where liquid surface water can exist on a planet’s surface is called the “habitable zone.” However, this definition is confined to our understanding of current and past life on Earth and the environments present on other planets. As researchers learn more and discover new environments in which life can sustain itself, the requirements for life on other planets may be redefined.

Different types of planets may drive processes that help or hinder habitability in different ways. For example, planets orbiting low-mass stars in the habitable zone may be tidally locked, with only one hemisphere facing the star at all times. Some planets may be limited to only periodic or local habitable regions on the surface if, e.g., they experience periodic global glaciations or are mostly desiccated. In order to understand the full range of planetary environments that could support life and generate detectable biosignatures, we require more detailed and complete models of diverse planetary conditions. In particular, understanding the processes that can maintain or lead to the loss of habitability on a planet requires the use of multiple coupled models that can examine these processes in detail, especially at the boundaries where these processes intersect each other.

Related Researchers

Vladimir Airapetian, Giada Arney, Tony Del Genio, Shawn Domagal-Goldman, Thomas Fauchez, Alex Glocer, Scott Guzewich, Nancy Kiang, Ravi Kopparapu, Weijia Kuang, Avi Mandell, Luke Oman, Jeremy Schnittman, Linda Sohl, Kostas Tsigaridis, Michael Way

Related SEEC Projects

  1. Arney et al. - "Atmos: Studies of Exoplanet Atmospheres Enabled by a Versatile 1-D Photochemical-Climate Model"
  2. Glocer et al. - "Dynamics of Upper Atmospheres of Terrestrial Exoplanets Around Active K to M dwarfs as a Factor of Habitability"
  3. Guzewich et al. - "Simulating Factors Influencing Habitable Exoplanets with ROCKE3D"
  4. Kiang et al. - "Land Planets: Foundations for Understanding the Distribution of Surface Habitability and Life Inside the Habitable Zone"
  5. Kuang et al. – "Habitability of Magnetic Exo Terrestrial Planets"
  6. Schnittman et al. - "Modeling eccentricity effects with chemistry-coupled GCM simulations"
  7. Way et al. - "Impact of Extreme Space Weather on Climates of Terrestrial-Type Exoplanets"
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