Gliese 581 d

2008-02-29T16:30:43Z

70.158.1.254:

{{Planetbox begin
| name = Gliese 581 d
}}
{{Planetbox image
| image = [[Image:Gliese 581 d-v1.jpg|270px]]
| caption = Artistic representation of a panoramic view of <br>Gliese 581 d, showing speculative moons.
}}
{{Planetbox star
| star = [[Gliese 581]]
| constell = [[Libra (constellation)|Libra]]
| RA = {{RA|15|19|26}}
| DEC = {{DEC|−07|43|20}}
| dist_ly = 20.4
| dist_pc = 6.27
| class = M2.5V
}}
{{Planetbox orbit
| period = 84.4
| semimajor = .25
| eccentricity = .2
| ang_dist = 39.936
| t_peri = 2452954.1
| semi-amp = 2.67
}}
{{Planetbox character
| mass_earth = >7.7
}}
{{Planetbox discovery
| discovery_date = [[2007-04-24]]
| discoverers = [[Stéphane Udry|Udry]] et al.
| discovery_method = Radial velocity
| discovery_status = unpublished
}}
{{Planetbox end}}

'''Gliese 581 d''' ({{pronEng|ˈgliːzə}}), also known as '''Wolf 562 d''' and '''HIP 74995 d''', is a "[[super-Earth]]" or large [[terrestrial planet| terrestrial]] [[extrasolar planet]] orbiting the [[red dwarf]] [[star]] [[Gliese 581]].<br />
Gliese 581 d is near the outer edge of the habitable zone. <ref>{{cite web |url=http://arxiv.org/PS_cache/arxiv/pdf/0705/0705.3758v1.pdf |title=The Habitability of Super-Earths in Gliese 581 |accessdate=2007-05-29 }}</ref>

== Discovery ==
The planet was discovered by the team of [[Stéphane Udry]] of the Geneva Observatory in [[Switzerland]] using the [[HARPS]] instrument on the [[European Southern Observatory]] 3.6 meter telescope in [[La Silla]], [[Chile]] on [[April 24]], [[2007]]. Udry's team employed the [[radial velocity]] technique, in which the size and mass of a planet are determined based on the small perturbations it induces in its parent star’s orbit via gravity.

The team is confident that the planet exists but recognizes that unlikely events could mimic its existence. They believe the issue will be settled by upcoming studies.

== Climate and habitability ==
Although Gliese 581 d orbits outside the theoretical [[habitable zone]] of its star, scientists surmise that conditions on the planet may be conducive to supporting life[http://www.space.com/scienceastronomy/070618_mm_gliese_581d.html]. Scientists originally believed that Gliese 581 d would in fact be too cold for liquid water to exist, and therefore could not support life as we understand it. However, due to a theorized [[greenhouse effect]], research now suggests that atmospheric conditions on the planet create temperatures at which water can exist, and therefore the planet may be capable of supporting life. It is important to note that these conditions are based on models of the planet, and have not been directly observed.

==References==
<references />
[http://obswww.unige.ch/~udry/udry_preprint.pdf Udry et al. (2007). "The HARPS search for southern extra-solar planets, XI. An habitable super-Earth (5 M⊕) in a 3-planet system". Astronomy and Astrophysics preprint]

== External links ==
*[http://vo.obspm.fr/exoplanetes/encyclo/planet.php?p1=Gl+581&p2=d '''Extrasolar Planets Encyclopaedia''': Gl 581 d]
*[http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=gl+581&NbIdent=1&Radius=10&Radius.unit=arcmin&CooFrame=FK5&CooEpoch=2000&CooEqui=2000&output.max=all&o.catall=on&output.mesdisp=N&Bibyear1=1983&Bibyear2=2005&Frame1=FK5&Frame2=FK4&Frame3=G&Equi1=200 '''SIMBAD''': V* HO Lib -- Variable Star]

{{Gliese 581}}

[[Category:Extrasolar planets]]
[[Category:Libra constellation]]

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Gliese 581 d