The first habitable exoplanet : a new candidate revealed by climate scientistsThe planetary system around the red dwarf Gliese 581, one of the closest stars to the Sun in the galaxy, has been the subject of several studies aiming to detect the first potentially habitable exoplanet. Two candidates have already been discarded, but a third planet, Gliese 581d, can be considered the first confirmed exoplanet that could support Earth-like life. This is the conclusion of a team of scientists from the Laboratoire de Métrologie Dynamique (CNRS/UPMC/ENS/Ecole Polytechnique) at the Institut Pierre Simon Laplace in Paris, France, whose study is published in "The Astrophysical Journal Letters".Read more
The planetary system around the red dwarf Gliese 581, one of the closest stars to the Sun in the galaxy, has been the subject of several studies aiming to detect the first potentially habitable exoplanet. Two candidates have already been discarded, but a third planet, Gliese 581d, can be considered the first confirmed exoplanet that could support Earth-like life. This is the conclusion of a team of scientists from the Laboratoire de Métrologie Dynamique (CNRS/UPMC/ENS/Ecole Polytechnique) at the Institut Pierre Simon Laplace in Paris, France, whose study is published in "The Astrophysical Journal Letters".
Title: Gliese 581d is the first discovered terrestrial-mass exoplanet in the habitable zoneAuthors: Robin Wordsworth, François Forget, Franck Selsis, Ehouarn Millour, Benjamin Charnay, Jean-Baptiste MadeleineIt has been suggested that the recently discovered exoplanet GJ581d might be able to support liquid water due to its relatively low mass and orbital distance. However, GJ581d receives 35% less stellar energy than Mars and is probably locked in tidal resonance, with extremely low insolation at the poles and possibly a permanent night side. Under such conditions, it is unknown whether any habitable climate on the planet would be able to withstand global glaciation and / or atmospheric collapse. Here we present three-dimensional climate simulations that demonstrate GJ581d will have a stable atmosphere and surface liquid water for a wide range of plausible cases, making it the first confirmed super-Earth (exoplanet of 2-10 Earth masses) in the habitable zone. We find that atmospheres with over 10 bar CO2 and varying amounts of background gas (e.g., N2) yield global mean temperatures above 0 degrees Celsius for both land and ocean-covered surfaces. Based on the emitted IR radiation calculated by the model, we propose observational tests that will allow these cases to be distinguished from other possible scenarios in the future. Read more (783kb, PDF)
Raymond Pierrehumbert at the University of Chicago examined the range of climates that Gliese 581 g might have and found one that would have a pool of water on one side, making it look like an eyeball. Even if further observations disprove the existence of Gliese 581 g, the work could help determine the habitability of exo-Earths still to be discovered.First spotted in September via wobbles in the light emitted by its host star, Gliese 581 g is likely to be rocky. That, combined with the fact that it orbits the star at just the right, "Goldilocks" distance to provide the warmth needed for liquid water, made it the first planet discovered outside our solar system with the potential to host life.
In September 2010, a group of astronomers at the Lick-Carnegie Exoplanet Survey announced the discovery of the first so-called "Goldilocks planet." Gliese 581g (also dubbed "Zarmina's World" by its discoverer, UC Santa Cruz astronomer Steven Vogt, who has romantically named the planet after his wife) is the first rocky planet outside our solar system known to be situated "just right" for life - that is, within the habitable zone of its star.
Last month, astronomers announced the discovery of the first potentially habitable extrasolar planet. But this week at an International Astronomical Union meeting, doubts were raised about the existence of this exciting new planet said to be orbiting the star Gliese 581.Called 'Gliese 581 g,' the planet was determined to be about 3 times the mass of Earth, meaning it was a rocky world, not a gas giant like Jupiter. Rocky extrasolar planets have been found before, but the unique trait about this planet was that it orbited within the red dwarf star's habitable zone, that region of space where temperatures are sufficient for water to remain as a liquid on a planetary surface.
Astronomers have detected an Earth-like exoplanet that may have just the right kind of conditions to support life.Gliese 581g lies some 20 light-years away in its star's "Goldilocks zone" - a region surface temperatures would allow the presence of liquid water.Scientists say that the newly found world could also potentially have an atmosphere.