The range of orbital distances around a star within which a planet could plausibly maintain liquid water on its surface given adequate atmospheric pressure, used in astrobiology as a first order proxy for potential habitability. The modern quantitative concept was developed by astrophysicist Su-Shu Huang in a series of papers in the 1950s and 1960s; exact boundary distances remain model dependent rather than fixed.
Facts
Disputed
Formulated YearMultiple researchers converged on the idea independently rather than one person formulating it: Hubertus Strughold introduced the related 'ecosphere' concept in 1953, the same year Harlow Shapley wrote about a 'liquid water belt'; the modern circumstellar habitable zone concept was then developed and formalized by Su-Shu Huang across a series of papers in the 1950s and 1960s. Proposed ByHubertus Strughold and Harlow Shapley (1953); formalized as the modern circumstellar habitable zone by Su-Shu Huang in the 1950s-1960s 1 Multiple researchers converged on the idea independently rather than one person formulating it: Hubertus Strughold introduced the related 'ecosphere' concept in 1953, the same year Harlow Shapley wrote about a 'liquid water belt'; the modern circumstellar habitable zone concept was then developed and formalized by Su-Shu Huang across a series of papers in the 1950s and 1960s. Concept Domain FAQs
Does a planet in the habitable zone guarantee it can support life?
No; the habitable zone marks where liquid water COULD exist, not where life is guaranteed.
No. The circumstellar habitable zone identifies where a planet could hold liquid water on its surface given an Earth-like atmosphere, but it does not by itself guarantee habitability. A planet inside the zone can still be uninhabitable for other reasons, such as a runaway greenhouse atmosphere, no atmosphere at all, or a lack of a protective magnetic field, and some researchers argue that worlds outside the traditional zone, including subsurface ocean moons and planets around certain long-lived stars, may be just as habitable or more so.
Connections
Associated With
Source Wikipedia (space and spaceflight articles)
Source Wikipedia (space and spaceflight articles)
Exoplanet, Concepts The habitable zone concept is a central tool for assessing exoplanet habitability.
Source Wikipedia (space and spaceflight articles)
Source Wikipedia (space and spaceflight articles)
Source Wikipedia (space and spaceflight articles)
Kepler was designed to find Earth-size planets in habitable zones.
Kepler-452b orbits within its star habitable zone
Proxima Centauri b orbits within its star's habitable zone.
Several TRAPPIST-1 planets orbit in or near the habitable zone
Sources
1. Wikipedia (space and spaceflight articles)
Wikimedia FoundationCircumstellar habitable zone, History section
Su-Shu Huang, an American astrophysicist developed the modern concept of circumstellar habitable zones in a series of papers in the 1950s and 60s.
- Associated With: Exoplanet
- Associated With: Drake Equation
- Associated With: Fermi Paradox
View the Source Habitable zone (Wikipedia)
Lead section
The alternative name, Goldilocks zone, is a metaphor, allusion and antonomasia of the children's fairy tale of "Goldilocks and the Three Bears", in which a little girl chooses from sets of three items, rejecting the ones that are too extreme (large or small, hot or cold, etc.), and settling on the one in the middle, which is "just right".
In Group: Habitability and the Detection of Life, Lead sentence
In astronomy and astrobiology, the habitable zone (HZ), also known as the circumstellar habitable zone (CHZ), or as the Goldilocks zone, is the range of orbits around a star within which a planetary surface could potentially support liquid water.
View the SourceDissenting Readings (1 dissenting reading)
Description
Heller and Armstrong (2014, 'Superhabitable Worlds') argue that the classic circumstellar habitable zone, defined mainly by where liquid surface water can exist on an Earth-like planet, is not the same question as where life or even more hospitable conditions than Earth's are most likely; they propose that some planets orbiting outside the traditional zone, around long-lived K-dwarf stars for example, could be more broadly habitable than Earth itself, and that subsurface ocean worlds can host liquid water entirely outside any circumstellar habitable zone.
A dissenting reading, from Rene Heller and John ArmstrongWikipedia (space and spaceflight articles), Wikimedia Foundation
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