{{short description|Martian valley}} {{Infobox feature on celestial object |name = Dao Vallis |image = [[Image:Dao Niger and Harmakhis Vallis PIA02810.jpg|250px]] |caption = Dao Vallis is the leftmost channel, joined just above the center of the image by [[Niger Vallis]]. In each valley water flowed toward the bottom of the image. The caldera of [[Hadriacus Mons]] is at upper left. |coordinates = {{coord|38.7|S|272.1|W|globe:mars_type:landmark|display=inline,title}} |length = 816.0 km |naming = Word for "star" in Thai }} '''Dao Vallis''' is a valley on [[Mars]] that appears to have been carved by water. It runs southwestward into [[Hellas Planitia]] from the southern slopes of the volcano [[Hadriacus Mons]], and has been identified as an [[outflow channel]].<ref>Carr, M.H. (2006), The Surface of Mars. Cambridge Planetary Science Series, Cambridge University Press.</ref> It and its [[tributary]], [[Niger Vallis]], extend for about {{convert|1200|km|mi|abbr=on}}.<ref>{{cite journal| bibcode=2003AGUFM.P11B1035C |title=Geologic Evolution of Dao Vallis, Mars|last1=Crown|first1=D. A.|last2=Bleamaster|first2=L. F.|last3=Mest|first3=S. C.|journal=AGU Fall Meeting Abstracts|year=2003|volume=2003|pages=P11B–1035}}</ref>
It is named after the [[Thai language|Thai]] word for [[star]], and it was proposed as a potential landing site for the 2012 [[Curiosity rover]] of the [[Mars Science Laboratory]] mission.<ref name="MSL Workshop Summary">{{cite web | url=http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop/docs/MSL_workshop_summary.pdf | title=MSL Workshop Summary | access-date=May 29, 2007 | date=April 27, 2007 }}</ref> In the fictional 2007 Canadian miniseries ''[[Race to Mars]]'', it is the landing site for ''Gagarin'', the lander.
== Origin == Dao Vallis begins near a large volcano, Hadriacus Mons, so it is thought to have received water when hot magma melted huge amounts of ice in the frozen ground. Much of this water may have been released in very large "outburst floods". The partially circular depressions on the left side of the channel in the image below suggests that groundwater sapping also contributed water more gradually.<ref>[http://themis.asu.edu/zoom-20020807a Dao Vallis (Released 7 August 2002)]</ref> <gallery> Image:Dao Vallis.JPG|Section of Dao Vallis, as seen by [[THEMIS]]. Click on image to see relationship of Dao Vallis to other nearby features.
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==See also== *[[Harmakhis Vallis]] *[[Outflow channels]] *[[Reull Vallis]]
==References== {{Reflist}} {{Commons category|Dao Vallis}}
==External links== * [http://www.google.com/mars/#lat=-36.102376&lon=91.076660&zoom=6&map=infrared&q=dao%20vallis Google Mars map centred on Dao Vallis].
{{Geography of Mars}} {{Portal bar|Solar System}} {{Authority control}}
[[Category:Valleys and canyons on Mars]] [[Category:Hellas quadrangle]]
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