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Until 2015, it was unclear whether Pluto or its largest moon, Charon, had mountains or valleys or even craters of impact. After the spectacular success of New Horizons in July 2015, scientists were surprised by the peaks and deep valleys that were revealed in the returned data. Now, thanks to the efforts of the New Horizons team, the first officially validated world map and the topographic maps of these two organizations have been published and are accessible to all. The maps and the process of their creation are described in two new research articles published in the journal Icarus.
To create the maps, New Horizons researchers, led by USRA Senior Scientist Paul Schenk, recorded all LORRI and Multispectral images. MVIC (Visible Imaging Camera) systems assemble and assemble mosaics. This work required a lot of manpower and required a detailed alignment of surface features in the overlapping images. The digital analysis of the stereoscopic images obtained by the two cameras was used to create topographic maps for each region; these were then assembled into integrated topographic maps for each body. These new maps of Pluto and Charon were produced meticulously over a two-year period as data was slowly transmitted to Earth from the New Horizons spacecraft. The quality of maps geographically and topographically accurate improved with each new series of images that had returned to Earth.
"It was one of the most complex and exciting global mapping projects I had the pleasure of participating in. Every time new images fell, something new was revealed, "explains Schenk. "The first thing to do was to understand the behavior of two different imaging systems in order to derive reliable topographic maps." Although preliminary maps of these bodies have been published before, these validated final maps represent the best understanding current surfaces. of these two important bodies.
The validated global map and topographic maps show the best resolution for each area illuminated by the Sun and their elevations. These maps reveal a rich variety of landforms on Pluto and Charon. The topographic maps confirm that the highest known mountains on Pluto are the Montes de Tenzing range, which formed along the southwestern margins of Spitnik Planitia's icy nitrogen cap. These steep-walled icy peaks have slopes of 40 ° or more and rise several kilometers above the Sputnik Planitia soil. The highest peak is about 6 kilometers (3.7 miles) above the base of the range, which is comparable to the Denali Crested Base Altitudes in Alaska and from Kilimanjaro to Kenya. The Pluto Mountains must be composed of rigid water ice in order to maintain their heights, as the more volatile ice seen on Pluto, including methane and nitrogen, would be too weak and the mountains would be too low. ; collapse.
Topographic maps also reveal scale functions that are not evident in the overall mosaic map. The thickness of the ice cap in the 1000-kilometer (625-mile) Planitia Sputnik is on average 2.5 kilometers (1.5 miles) while the outer edges of the ice cap are deeper than 3, 5 km (2.2 miles) below average Pluto elevation or surface "sea level". While most of the ice cap is relatively flat, these outer ridges of Sputnik Planitia are the lowest known areas on Pluto, all features that are evident only in stereo images and altitude maps. The topographic maps also reveal the existence of a system of ridges and troughs deeply eroded on a global scale, along more than 3000 kilometers (1864 miles), oriented from north to south near the western boundary of Sputnik Planitia. This feature is the longest known on Pluto and indicates that extensive fracturing has occurred in the distant past. The principal investigator of the New Horizons mission, Alan Stern, of the Southwest Research Institute, noted: "The degree of topographic relief of Pluto in the hemisphere that we have explored with New Horizons. is really amazing, I can not wait to see the other side of Pluto revealed in detail by a future mission to orbit around the planet. "
On Charon, the topographic maps also reveal deep depressions near the North Pole that are ~ 14 kilometers (8.7 miles) deep, deeper than the Mariana Trench on Earth.The equatorial depressions that form the boundary between the north and south plains of Charon also have a high elevation of about 8 kilometers, and the mapping of north fractured terrain and crustal blocks inclined along this boundary could be due to cryovolcanic resurfacing, possibly caused by the sinking of large crustal blocks in the deep interior of Charon Ross Beyer, research scientist at the SETI Institute in California, with the additional help of the United States Geological Survey (USGS), explains: " These satellites and others make Charon the most robust satellites of average size other than Saturn's Iapetus, which participated in mapping efforts and is co-author of the Icarus articles. The rugged terrain also indicates that Charon retains much of its original topography due to its history of fracking and surface disturbance.
The global images and topographic maps of Pluto and Charon have been archived in the Planetary Data System and will be available to the scientific community and the public.
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Pluto and Charon's global maps of images and topographies have been archived in the Planetary Data System (pds.nasa.gov) and will be be used by the scientific community and the public. [19659011]
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