{{Short description|Crater on Mars}} {{Infobox feature on celestial object |name = Tractus Catena |image = [[Image:Tractus Fossae based on day THEMIS.png|200px]] |caption = Tractus Catena based on [[Thermal Emission Imaging System|THEMIS]] day-time image |coordinates = {{coord|28.17|N|102.77|W|globe:mars_type:landmark|display=inline,title}} }} '''Tractus Catena''' is a set of pits in the [[Arcadia quadrangle]] of [[Mars]]. Its location is centered at {{Coord|28.17|N|102.77|W|globe:Mars}} . It is {{convert|897|km|mi|abbr=on}} long and was named after a classical albedo feature name.<ref>{{cite web|title=Gazetteer of Planetary Nomenclature {{!}} Tractus Catena|url=https://planetarynames.wr.usgs.gov/Feature/6074|website=usgs.gov|publisher=[[International Astronomical Union]]|access-date=4 March 2015}}</ref> The term "Catena" refers to a chain of craters.<ref>{{Cite web|url=https://planetarynames.wr.usgs.gov/DescriptorTerms|title = Planetary Names: Feature Types}}</ref>
The line of pits that make up Tractus Catena make it related to [[Fossa (geology)|fossa]] which are common on Mars.
Dark slope streaks are visible in one of the pictures below. Such streaks are common on Mars. They occur on steep slopes of craters, troughs, and valleys. The streaks are dark at first. They get lighter with age.<ref>{{cite journal | last1 = Schorghofer | first1 = N |display-authors=etal | year = 2007 | title = Three decades of slope streak activity on Mars | journal = Icarus | volume = 191 | issue = 1| pages = 132–140 | doi=10.1016/j.icarus.2007.04.026 | bibcode=2007Icar..191..132S}}</ref> Sometimes they start in a tiny spot, then spread out and go for hundreds of meters. They have been seen to travel around obstacles, like boulders.<ref>http://www.space.com/image_of_day_080730.html {{Dead link|date=February 2022}}</ref> It is believed that they are avalanches of bright dust that expose a darker underlying layer.
<gallery class="center" widths="190px" heights="180px" > Image:Tractus Catena.JPG|Tractus Catena, as seen by [[HiRISE]]. Scale bar is {{convert|1000|m|ft|abbr=on}} long. Click on image for good view of [[Dark Slope Streaks|dark slope streaks]] Image:Tractus Catena Floor.JPG|Tractus Catena Floor, as seen by HiRISE. Scale bar is {{convert|500|m|ft|abbr=on}} long. </gallery>
== References == {{reflist}}
==See also==
* [[Dark Slope Streaks]] * [[Fossa (geology)]] * [[Geology of Mars]] * [[HiRISE]]
{{commons category|Tractus Catena}} {{Geography of Mars}}
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[[Category:Arcadia quadrangle]] [[Category:Impact craters on Mars|#]]
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