Difference between revisions 920372146 and 920543276 on enwiki

{{redirect|Goldilocks Zone|the more general principle|Goldilocks principle}}
{{redirect|Habitable zone|the galactic zone|Galactic habitable zone}}
{{short description|Zone around a star with strong possibilities for stable liquid water on a suitable planet}}
(contracted; show full)

{| class="wikitable sortable"
|- style="text-align:center; align:center; background:#90b0f0;"
|+ Estimates of the circumstellar habitable zone boundaries of the Solar System
! Inner edge ([[Astronomical unit|AU]]) !! Outer edge (AU) !! Year !! Notes
|-
| 0.725 || 1.24 || 
Dole 19641964, Dole<ref name=dole-1964 />  || Used optically thin atmospheres and fixed albedos. Places the aphelion of Venus just inside the zone.
|-
| || 1.385–1.398 || 1969, Budyko 1969<ref name=budyko-1969>{{Cite journal | last1 = Budyko | first1 = M. I. | title = The effect of solar radiation variations on the climate of the Earth | doi = 10.1111/j.2153-3490.1969.tb00466.x | journal = Tellus | volume = 21 | issue = 5 | pages = 611–619 | year = 1969 | pmid =  | pmc = | bibcode = 1969TellA..21..611B| citeseerx = 10.1.1.696.824 }}</ref>  || Based on studies of ice albedo feedback models to determine the point at which Earth would experience global glaciation. This estimate was supported in studies by Sellers 1969<ref>{{cite journal |title=A Global Climatic Model Based on the Energy Balance of the Earth-Atmosphere System |author=Sellers, William D. |journal=Journal of Applied Meteorology |date=June 1969 |volume=8 |issue=3 |pages=392–400 |doi=10.1175/1520-0450(1969)008<0392:AGCMBO>2.0.CO;2 |doi-access=free |bibcode=1969JApMe...8..392S}}</ref> and North 1975.<ref>{{cite journal
 |last1 = North
 |first1 = Gerald R.
 |date=November 1975
 |title = Theory of Energy-Balance Climate Models
 |journal = Journal of the Atmospheric Sciences
 |volume = 32
 |issue = 11
 |pages = 2033–2043
 |doi = 10.1175/1520-0469(1975)032<2033:TOEBCM>2.0.CO;2
|doi-access=free
 |bibcode = 1975JAtS...32.2033N
 }}</ref>
|-
| 0.88–0.912 || || 1970, Rasool and De Bergh 1970<ref name=rasool-1970>{{cite journal | pages = 1037–1039 | issue = 5250 | volume = 226 | date = Jun 1970 | doi = 10.1038/2261037a0 | pmid = 16057644 | issn = 0028-0836 | journal = Nature | first2 = C. | first1 = I. | title = The Runaway Greenhouse and the Accumulation of CO<sub>2</sub> in the Venus Atmosphere | url = http://pubs.giss.nasa.gov/docs/1970/1970_Rasool_DeBergh_1.pdf | last1 = Rasool | format =  | last2 = De Bergh | bibcode = 1970Natur.226.1037R }}{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>|| Based on studies of Venus's atmosphere, Rasool and De Bergh concluded that this is the minimum distance at which Earth would have formed stable oceans.
|-
| 0.95 || 1.01 || 1979, Hart et al. 1979<ref name=hart-1979>{{Cite journal | last1 = Hart | first1 = M. H. | doi = 10.1016/0019-1035(79)90141-6 | title = Habitable zones about main sequence stars | journal = Icarus | volume = 37 | issue = 1 | pages = 351–357 | year = 1979 | pmid =  | pmc = |bibcode = 1979Icar...37..351H }}</ref>  || Based on computer modelling and simulations of the evolution of Earth's atmospheric composition and surface temperature. This estimate has often been cited by subsequent publications.
|-
| || 3.0 || Fogg 19921992, Fogg<ref name=fogg-1992>{{cite journal |title=An Estimate of the Prevalence of Biocompatible and Habitable Planets |author=Fogg, M. J. |journal=Journal of the British Interplanetary Society |date=1992 |volume=45 |pages=3–12 |bibcode=1992JBIS...45....3F |pmid=11539465 |issue=1}}</ref>|| Used the [[carbon cycle]] to estimate the outer edge of the circumstellar habitable zone.
|-
| 0.95 || 1.37 || 1993, Kasting et al. 1993<ref name=kasting-1993 />|| Founded the most common working definition of the habitable zone used today. Assumes that CO<sub>2</sub> and H<sub>2</sub>O are the key greenhouse gases as they are for the Earth. Argued that the habitable zone is wide because of the [[carbonate-silicate cycle]]. Noted the cooling effect of cloud albedo. Table shows conservative limits. Optimistic limits were 0.84–1.67 AU.
|-
| || 2.0 || 2010, Spiegel et al. 2010<ref name="speigel-2010">{{Cite journal | last1 = Spiegel | first1 = D. S. | last2 = Raymond | first2 = S. N. | last3 = Dressing | first3 = C. D. | last4 = Scharf | first4 = C. A. | last5 = Mitchell | first5 = J. L. | title = Generalized Milankovitch Cycles and Long-Term Climatic Habitability | doi = 10.1088/0004-637X/721/2/1308 | journal = The Astrophysical Journal | volume = 721 | issue = 2 | pages = 1308–1318 | year = 2010 | pmid =  | pmc = |arxiv = 1002.4877 |bibcode = 2010ApJ...721.1308S }}</ref>  || Proposed that seasonal liquid water is possible to this limit when combining high obliquity and orbital eccentricity.
|-
| 0.75 || || 2011, Abe et al. 2011<ref name="abe-2011">{{Cite journal | last1 = Abe | first1 = Y. | last2 = Abe-Ouchi | first2 = A. | last3 = Sleep | first3 = N. H. | last4 = Zahnle | first4 = K. J. | title = Habitable Zone Limits for Dry Planets | doi = 10.1089/ast.2010.0545 | journal = Astrobiology | volume = 11 | issue = 5 | pages = 443–460 | year = 2011 | pmid =  21707386| pmc = |bibcode = 2011AsBio..11..443A }}</ref>  || Found that land-dominated "desert planets" with water at the poles could exist closer to the Sun than watery planets like Earth.
|-
|  ||10  || 2011, Pierrehumbert and Gaidos 2011<ref name= rayeric-2011 />  ||Terrestrial planets that accrete tens-to-thousands of bars of primordial hydrogen from the protoplanetary disc may be habitable at distances that extend as far out as 10 AU in our solar system.
|-
| 0.77–0.87 || 1.02–1.18 || 2013, Vladilo et al. 2013<ref name=vladilo-2013>{{cite journal |url=http://iopscience.iop.org/0004-637X/767/1/65/ |title=The habitable zone of Earth-like planets with different levels of atmospheric pressure |author1=Vladilo, Giovanni |author2=Murante, Giuseppe |author3=Silva, Laura |author4=Provenzale, Antonello |author5=Ferri, Gaia |author6=Ragazzini, Gregorio |journal=The Astrophysical Journal |date=March 2013 |volume=767 |issue=1 |pages=65–? |doi=10.1088/0004-637X/767/1/65 |arxiv=1302.4566|bibcode = 2013ApJ...767...65V }}</ref>  || Inner edge of circumstellar habitable zone is closer and outer edge is farther for higher atmospheric pressures; determined minimum atmospheric pressure required to be 15 [[millibar]].
|-
| 0.99 || 1.70 || 2013, Kopparapu et al. 2013<ref name=kopparapu-2013 /><ref name="Kopparapu2013b" />  || Revised estimates of the Kasting et al. (1993) formulation using updated moist greenhouse and water loss algorithms. According to this measure Earth is at the inner edge of the HZ and close to, but just outside, the moist greenhouse limit. As with Kasting et al. (1993), this applies to an Earth-like planet where the "water loss" (moist greenhouse) limit, at the inner edge of the habitable zone, is where the temperature has reached around 60 Celsius and is high enough, right up into the troposphere, that the atmosphere has become fully saturated with water vapour. Once the stratosphere becomes wet, water vapour photolysis releases hydrogen into space. At this point cloud feedback cooling does not increase significantly with further warming. The "maximum greenhouse" limit, at the outer edge, is where a {{CO2}} dominated atmosphere, of around 8 bars, has produced the maximum amount of greenhouse warming, and further increases in {{CO2}} will not create enough warming to prevent {{CO2}} catastrophically freezing out of the atmosphere. Optimistic limits were 0.97–1.70 AU. This definition does not take into account possible radiative warming by {{CO2}} clouds.
|-
| 0.38 || || 2013, Zsom et al. 2013<br /><ref name=zsom-2013>{{cite journal |title=Towards the Minimum Inner Edge Distance of the Habitable Zone |last=Zsom |first=Andras |date=2013 |arxiv=1304.3714 |last2=Seager |first2=Sara |last3=De Wit |first3=Julien |doi=10.1088/0004-637X/778/2/109 |volume=778 |issue=2 |journal=The Astrophysical Journal |page=109 |bibcode=2013ApJ...778..109Z}}</ref>  || Estimate based on various possible combinations of atmospheric composition, pressure and relative humidity of the planet's atmosphere.
|-
| 0.95  ||  || 2013, Leconte et al. 2013<ref name= leconte-2013>{{cite journal |title=Increased insolation threshold for runaway greenhouse processes on Earth like planets |last=Leconte |first=Jeremy |date=2013 |arxiv=1312.3337 |last2=Forget |first2=Francois |last3=Charnay |first3=Benjamin |last4=Wordsworth |first4=Robin |last5=Pottier |first5=Alizee |doi=10.1038/nature12827 |pmid=24336285 |volume=504 |issue=7479 |pages=268–71 |journal=Nature |bibcode=2013Natur.504..268L}}</ref>  ||Using 3-D models, these authors computed an inner edge of 0.95 AU for our solar system.
|-
| 0.95 ||2.4 || 2017, Ramirez and Kaltenegger 2017<br /><ref name=rk-2017>{{cite journal |title=A Volcanic Hydrogen Habitable Zone |last=Ramirez |first=Ramses |date=2017 |arxiv=1702.08618|last2=Kaltenegger |first2=Lisa |doi=10.3847/2041-8213/aa60c8 |volume=837 |issue=1 |pages=L4 |journal=The Astrophysical Journal Letters|bibcode=2017ApJ...837L...4R}}</ref>  || An expansion of the classical carbon dioxide-water vapor habitable zone <ref name=kasting-1993 /> assuming a volcanic hydrogen atmospheric concentration of 50%.
|}

===Extrasolar extrapolation===
{{see also|Habitability of red dwarf systems|Habitability of orange dwarf systems}}
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