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{{Short description|Largest crater on Phobos}}

factoids

}}9mi|abbr=on}}| discoverer = Asaph HallAngeline Stickney>Chloe Angeline Stickney Hall }} Stickney is the largest crater on Phobos, which is a satellite of Mars. It is {{convert|9|km|mi|abbr=on}} in diameter, taking up a substantial proportion of the moon's surface.

Naming

The crater is named after mathematician Chloe Angeline Stickney Hall, the wife of Phobos' discoverer Asaph Hall, whose support was credited by her husband as critical for his discovery of the moon.BOOK, Hall, Angelo, An astronomer's wife, Baltimore, Nunn and Company, 1908, 997037, 112, The crater was named in 1973, based on Mariner 9 images, by an IAU nomenclature committee chaired by Carl Sagan.JOURNAL, A Mariner 9 atlas of the moons of Mars, Veverka, Joseph, et al, Icarus (journal), Icarus, Elsevier, 23, 2, 206–289, 1974, 10.1016/0019-1035(74)90006-2, 1974Icar...23..206V, .

Formation

There are two models for the age of Stickney, based on the differing possible dates at which Phobos began to orbit around Mars. If Phobos has been orbiting for 4.3 Ga (billion years) then Stickney formed 4.2 Ga ago, but if Phobos has only been orbiting for 3.5 Ga then it formed 2.6 Ga ago.JOURNAL,weblink The age of Phobos and its largest crater, Stickney, Planetary and Space Science, Schmedermann, Nico, et al, November 1, 2014, August 9, 2022, 152–163, 102, Elsevier, 10.1016/j.pss.2014.04.009, The impact created a large amount of ejecta which escaped Phobos' gravity and entered into orbit around Mars for a period not exceeding 1000 years, some of this material then crashed back onto Phobos and created secondary impact craters.JOURNAL,weblink The Stickney Crater ejecta secondary impact crater spike on Phobos: Implications for the age of Stickney and the surface of Phobos, Planetary and Space Science, Elsevier, Ramsley, Kenneth R., Head, James W., April 2017, August 12, 2022, 138, 7–24, 10.1016/j.pss.2017.02.004, The majority of craters on Phobos that are smaller than 600 meters in diameter were caused by these secondary impacts.JOURNAL,weblink Stickney Crater: Secondary Impacts, Boulders, Grooves, and the Surface Age of Phobos, Lunar and Planetary Science Conference, 50th Lunar and Planetary Science Conference, Brown University, Ramsley, Kenneth R., Head, James W., 2019, 2132, 1, August 24, 2022,

Physical features

Grooves and crater chains appear to radiate from Stickney. One theory suggests that they were formed as a result of stresses from the impact that created the crater; if true this suggests that said impact nearly destroyed Phobos. There are however numerous other theories for how they were made, such as that they were formed by material ejected from impacts on Mars,WEB, Murray, John B., et al,weblink New evidence on the origin of Phobos' parallel grooves from HRSC Mars Express, Lunar and Planetary Science Conference, Lunar and Planetary Institute & Johnson Space Center, 2006, that they were created by tidal forces exerted by Mars,WEB, Zubritsky, Elizabeth, Mars' Moon Phobos is Slowly Falling Apart,weblink Goddard Space Flight Center, NASA, November 11, 2015, November 11, 2015, or that they were created by boulders rolling along Phobos' surface following the Stickney impact.WEB, Gough, Evan, Strange Grooves on Phobos Were Caused by Boulders Rolling Around on its Surface,weblink 20 November 2018, Universe Today, 21 November 2018, JOURNAL, Ramsley, Kenneth R., Head, James W., Origin of Phobos grooves: Testing the Stickney Crater ejecta model, 16 November 2018, Planetary and Space Science, Elsevier, 165, 137–147, 10.1016/j.pss.2018.11.004, 86859432, Regardless of the causes of these grooves, the impact of the object which created Stickney was large enough to have potentially destroyed Phobos; a 2016 study by Syal et al. found that the high porosity of the moon was critical in preventing it from being destroyed during the collision.JOURNAL, Excavating Stickney crater at Phobos, Geophysical Research Letters, American Geophysical Union, Syal, Megan Bruck, et al, October 8, 2016, 43, 20, 10595–10601, 10.1002/2016GL070749, 131912268, free, It is possible that the area underneath Stickney is much denser and less porous than the rest of Phobos, though models of the moon's interior vary on this.JOURNAL,weblink Signature of Phobos' interior structure in its gravity field and libration, Icarus (journal), Icarus, Elsevier, March 15, 2019, Le Maistre, Simon, Rivoldini, Attilio, Rosenblatt, Pascal, August 15, 2022, 10.1016/j.icarus.2018.11.022, 321, 272–290, 125563790, Stickney has a noticeable lineated texture on its interior walls, caused by landslides from materials falling into the crater.WEB, April 9, 2008, Phobos from 6,800 Kilometers (Color), NASA, Jet Propulsion Laboratory & University of Arizona,weblink April 9, 2008, April 12, 2008,weblink" title="web.archive.org/web/20080412015258weblink">weblink dead, There is a noticeable blue spectral coloration on the south-western edge of the crater, which is theorized to be a relatively thin layer of rock.JOURNAL,weblink Spectral heterogeneity on Phobos and Deimos: HiRISE observations and comparisons to Mars Pathfinder results, Planetary and Space Science, Elsevier, Thomas, Nathan, et al, October 2011, August 18, 2022, 1281–1292, 59, 13, 10.1016/j.pss.2010.04.018, Said coloration was likely caused by a combination of material from Stickney itself and from the smaller crater of Limtoc.JOURNAL,weblink Simulating re-impacts from craters at the deepest location of Phobos to generate its blue spectral units, Icarus (journal), Icarus, Elsevier, 354, 10.1016/j.icarus.2020.113997, Kikuchi, Hiroshi, January 15, 2021, 113997, 224926793, August 5, 2022,

See also

• Moons of Mars
• Deimos (moon)

References

{{Reflist}}

External links

{{Commons category}}

• Flight around Phobos (animated movie)
• Stickney in High Resolution
• Stickney at APOD, 2018 May 5
• Creation of Stickney Crater on Phobos (VIDEO) {{Webarchive|url=https://web.archive.org/web/20180914203440weblink |date=2018-09-14 }} simulation which shows how Stickney crater was created, and how it affected Phobos, The Lawrence Livermore National Laboratory

{{Mars}}