PIA00317.jpg = PIA00317: Global Color Mosaic of Triton
Global color mosaic of Triton, taken in 1989 by Voyager 2 during its flyby of the Neptune system. Color was synthesized by combining high-resolution images taken through orange, violet, and ultraviolet filters; these images were displayed as red, green, and blue images and combined to create this color version. With a radius of 1,350 (839 mi), about 22% smaller than Earth's moon, Triton is by far the largest satellite of Neptune. It is one of only three objects in the Solar System known to have a nitrogen-dominated atmosphere (the others are Earth and Saturn's giant moon, Titan). Triton has the coldest surface known anywhere in the Solar System (38 K, about -391 degrees Fahrenheit); it is so cold that most of Triton's nitrogen is condensed as frost, making it the only satellite in the Solar System known to have a surface made mainly of nitrogen ice. The pinkish deposits constitute a vast south polar cap believed to contain methane ice, which would have reacted under sunlight to form pink or red compounds. The dark streaks overlying these pink ices are believed to be an icy and perhaps carbonaceous dust deposited from huge geyser-like plumes, some of which were found to be active during the Voyager 2 flyby. The bluish-green band visible in this image extends all the way around Triton near the equator; it may consist of relatively fresh nitrogen frost deposits. The greenish areas includes what is called the cantaloupe terrain, whose origin is unknown, and a set of "cryovolcanic" landscapes apparently produced by icy-cold liquids (now frozen) erupted from Triton's interior.
Voir l'image PIA00317: Global Color Mosaic of Triton sur le site de la NASA.PIA02208: Triton
Voyager 2 took this picture of Neptune's largest satellite,Triton, from less than 80,000 km (50,000 miles). The image shows an area in Triton's northern hemisphere. The Sun is just above the horizon, so features cast shadows that accentuate height differences. The large, smooth area in the right-hand side of the image shows a single, fresh, impact crater. Otherwise there is no evidence of impacts such as those that have pocked the faces of most of the satellites Voyager 2 has visited. Many low cliffs in the area, bright where they face the Sun, and when they face away from it, suggest and intricate history for Triton. The cliffs might be due either to melting of surface materials or, possibly, caused by unusual fluid materials that flowed sometime in Triton's past. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA02208: Triton sur le site de la NASA.PIA00056: Triton - Detail of Dark and Light Material
Voyager 2 acquired this black and white image of Triton, Neptune's largest satellite, during the night of Aug. 24-25, 1989. Triton's limb cuts obliquely across the middle of the image. The field of view is about 1,000 km (600 miles) across. Three irregular dark areas, surrounded by brighter material, dominate the image. Low-lying material with intermediate albedo occupies the central area, and fresh craters occur along the right margin. Sub-parallel alignment of linear patches of dark material shown in the lower and left part of the image suggests that the patches are structurally controlled. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA00056: Triton - Detail of Dark and Light Material sur le site de la NASA.PIA02246: Voyager's Color Image of Triton
Features as small as 100 km (62 miles) across can be seen in this color image of Neptune's satellite Triton, photographed by Voyager 2 on Aug. 20, 1989, while it was still 5.4 million km (3.3 million miles) from Neptune. Triton's overall pinkish color may be due to reddish materials produced by irradiation of methane gas and ice on the satellite. The dark areas near the top of the image seem to be part of a belt of dark markings observed near Triton's equator at different longitudes. Generally, darker areas on Triton appear to be somewhat redder in color than brighter areas. The central longitude in the image is 123 degrees. Here the south pole is at about 6 o'clock, approximately one sixth of the way up from the bottom. The color image was made from three black and white frames, taken through clear, violet and green filters. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA02246: Voyager's Color Image of Triton sur le site de la NASA.
PIA02234: Triton's Surface Topography
Voyager 2 was 530,000 kilometers (330,000 miles) from Neptune's largest satellite, Triton, when this photo was taken, Aug. 24, 1989. With a resolution of 10 kilometers (6 miles), this is the first photo of Triton to reveal surface topography. The south pole, continuously illuminated by sunlight at this season, is at bottom left. The boundary between the bright southern hemisphere and the darker northern hemisphere is clearly visible. Both the darker regions to the north and the very bright sub-equatorial band show a complex pattern of irregular topography that somewhat resembles "fretted terrain" on parts of Venus and Mars. The pattern of dark and light regions over most of the southern hemisphere will require higher-resolution images for interpretation. Also evident are long, straight lines that appear to be surface expressions of internal, tectonic processes. No large impact craters are visible, suggesting that the crust of Triton has been renewed relatively recently that is, within the past billion years or less. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA02234: Triton's Surface Topography sur le site de la NASA.
PIA02211: Triton
Voyager 2 obtained this color image of Triton at a distance of 4 million kilometers (2.5 million miles) at 1 a.m. PDT on Aug. 22, 1989. The picture was made by combining images taken through the green, clear and violet filters. The smallest features seen are about 74 kilometers (46 miles) across. The south pole of Triton is currently tipped toward the sun and it is summer in the southern hemisphere. The south pole is located about a quarter of the way up from the bottom of the image. The bright band near the top of the image nearly coincides with the equator of Triton. One prominent and several smaller bright, wispy streaks extend from the band into the darker northern hemisphere. The prominent wispy streak shows a bluish-white color while the darker northern hemisphere is reddish in color. This may indicate that the streak is freshly deposited frost while the red color in the northern hemisphere may result from methane frost that has been darkened by radiation. Individual markings appear to rotate with the satellite and retain their shapes indicating they are indeed surface features and not in the tenuous atmosphere. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA02211: Triton sur le site de la NASA.PIA02216: Triton Mosaic
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PIA02235.jpg = PIA02235: Triton Mosaic
This picture of Triton is a mosaic of the highest resolution images taken by Voyager 2 on Aug. 25, 1989 from a distance of about 40,000 kilometers (24,800 miles). The mosaic is superimposed on the lower resolution mapping images taken about 2 hours earlier in order to fill in gaps between high resolution images. The smallest features that can be seen on the images are about 0.8 kilometers (0.5 miles) across. The terminator (line separating day and night) is at the top of the picture and is centered at about 30 degrees north latitude and 330 degrees longitude. These highest resolution images were targeted for the terminator region to show details of the topography by the shadows it casts. Near the center of the picture is a depression filled with smooth plains that are probably ices which were once erupted in a fluid state. The depth of the depression is about 300 meters (900 feet) and the prominent fresh impact crater on its floor is about 20 kilometers (12 miles) in diameter and about 1 kilometer (0.6 mile) deep. On the right is an elongate crater with adjacent dark deposits above it. This feature may be an explosive eruption vent formed by gaps within the ice. The linear structure on the left is probably a fracture along which fresh ice has been extruded. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA02235: Triton Mosaic sur le site de la NASA.
PIA00059: Triton South Polar Terrain
This image of the south polar terrain of Triton, taken on Aug. 25, 1989 reveals about 50 dark plumes or 'wind streaks' on the icy surface. The plumes originate at very dark spots generally a few miles in diameter and some are more than 100 miles long. The spots which clearly mark the source of the dark material may be vents where gas has erupted from beneath the surface and carried dark particles into Triton's nitrogen atmosphere. Southwesterly winds then transported the erupted particles, which formed gradually thinning deposits to the northeast of most vents. It is possible that the eruptions have been driven by seasonal heating of very shallow subsurface deposits of volatiles, and the winds transporting particles similarly may be seasonal winds. The polar terrain, upon which the dark streaks have been deposited, is a region of bright materials mottled with irregular, somewhat dark patches. The pattern of irregular patches suggests that they may correspond to lag deposits of moderately dark material that cap the bright ice over the polar terrain. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA00059: Triton South Polar Terrain sur le site de la NASA.PIA00340: Montage of Neptune and Triton
This computer generated montage shows Neptune as it would appear from a spacecraft approaching Triton, Neptune's largest moon at 2706 km (1683 mi) in diameter. The wind and sublimation-eroded south polar cap of Triton is shown at the bottom of the Triton image, a cryovolcanic terrain at the upper right, and the enigmatic "cantaloupe terrain" at the upper left. Triton's surface is mostly covered by nitrogen frost mixed with traces of condensed methane, carbon dioxide, and carbon monoxide. The tenuous atmosphere of Triton, though only about one-hundredth of one percent of Earth's atmospheric density at the surface, is thick enough to produce wind-deposited streaks of dark and bright materials of unknown composition in the south polar cap region. The southern polar cap was sublimating at the time of the Voyager 2 flyby, as indicated by the irregular and eroded appearance of the edge of the cap. The polar frosts were sublimating because Triton's orbital and rotational motion causes the sun to shine directly on the polar cap for a period of several decades during Neptune's and Triton's long austral summer. Though the polar cap was undergoing "heat death," surface temperatures still were only about 38 K (-391 degrees Fahrenheit).
Voir l'image PIA00340: Montage of Neptune and Triton sur le site de la NASA.
PIA02247: Voyager's Parting Shot of Triton
Voyager 2 obtained this parting shot of Triton, Neptune's largest satellite, shortly after closest approach to the moon and passage through its shadow on the morning of Aug. 25, 1989. The distance to Triton was 90,000 kilometers (56,000 thousand miles) and the phase angle was 155 degrees, so that only a thin crescent of Triton's south polar region can be seen. This image was assembled using the green, blue and violet filters of Voyager's wide angle camera. Because of the high phase angle, and perhaps because of scattering sunlight in Triton's hazy atmosphere, few surface features are discernible. Faint linear markings near the center of the crescent may be shadows case by surface features or by clouds, and the brightness of the left (western) horn of the crescent compared to the right horn may be a result of variable haze in the atmosphere. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA02247: Voyager's Parting Shot of Triton sur le site de la NASA.
PIA00344: Neptune on Triton's Horizon
Composite view showing Neptune on Triton's horizon. Neptune's south pole is to the left; clearly visible in the planets' southern hemisphere is a Great Dark Spot, a large anticyclonic storm system located about 20 degrees South. The foreground is a computer generated view of Triton's maria as they would appear from a point approximately 45 km above the surface. The terraces visible in this image indicate multiple episodes of 'cryovolcanic' flooding. This three-dimensional view was created from a Voyager image by using a two-dimensional photoclinometric model. Relief has been exaggerated roughly 30-fold, the actual range of the relief is about 1 km. Would Neptune appear to be rising or setting? Neither, due to the motion of Triton relative to Neptune, it would appear to move laterally along the horizon, eventually rising and setting at high latitudes.
Voir l'image PIA00344: Neptune on Triton's Horizon sur le site de la NASA.PIA00061: Triton High Resolution View of Northern Hemisphere
This is one of the most detailed views of the surface of Triton taken by Voyager 2 on its flyby of the large satellite of Neptune early in the morning of Aug. 25, 1989. The picture was stored on the tape recorder and relayed to Earth later. Taken from a distance of only 40,000 km (25,000 miles), the frame is about 220 kilometers (140 miles) across and shows details as small as 750 meters (0.5 miles). Most of the area is covered by a peculiar landscape of roughly circular depressions separated by rugged ridges. This type of terrain, which covers large tracts of Triton's northern hemisphere, is unlike anything seen elsewhere in the solar system. The depressions are probably not impact craters: They are too similar in size and too regularly spaced. Their origin is still unknown, but may involve local melting and collapse of the icy surface. A conspicuous set of grooves and ridges cuts across the landscape, indicating fracturing and deformation of Triton's surface. The rarity of impact craters suggests a young surface by solar system standards, probably less than a few billion years old. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA00061: Triton High Resolution View of Northern Hemisphere sur le site de la NASA.PIA01536: Detail of Triton's Surface
This color photo of Neptune's large satellite Triton was obtained on Aug. 24 1989 at a range of 530,000 kilometers (330,000 miles). The resolution is about 10 kilometers (6.2 miles), sufficient to begin to show topographic detail. The image was made from pictures taken through the green, violet and ultraviolet filters. In this technique, regions that are highly reflective in the ultraviolet appear blue in color. In reality, there is no part of Triton that would appear blue to the eye. The bright southern hemisphere of Triton, which fills most of this frame, is generally pink in tone as is the even brighter equatorial band. The darker regions north of the equator also tend to be pink or reddish in color.
JPL manages the Voyager project for NASA's Office of Space Science.
Voir l'image PIA01536: Detail of Triton's Surface sur le site de la NASA.
PIA02203: Limb clouds over Triton
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PIA01538.jpg = PIA01538: Complex Geologic History of Triton
Part of the complex geologic history of icy Triton, Neptune's largest satellite, is shown in this Voyager 2 photo, which has a resolution of 900 meters (2,700 feet) per picture element. The photo was received as part of a Triton-mapping sequence between 3:30 and 5:30 a.m. (PDT). This view is about 500 kilometers (300 miles) across. It encompasses two depressions, possibly old impact basins, that have been extensively modified by flooding, melting, faulting, and collapse. Several episodes of filling and partial removal of material appear to have occurred. The rough area in the middle of the bottom depression probably marks the most recent eruption of material. Only a few impact craters dot the area, which shows the dominance of internally driven geologic processes on Triton.
JPL manages the Voyager project for NASA's Office of Space Science.
Voir l'image PIA01538: Complex Geologic History of Triton sur le site de la NASA.
PIA02212: Triton
The smallest features that can be seen in this false color image of Neptune's largest satellite, Triton, are about 47 km (29 miles) across. The image, taken by Voyager 2 early in the morning of Aug. 23, 1989, is a composite of three images taken through ultraviolet, green, and violet filters. The image offers an example of the kinds of puzzles scientists face on the eve of an encounter: Mottling in the bright southern hemisphere may be the result of topography, if Triton's crust is predominantly water ice, which is rigid at Triton's surface temperature. Alternatively, the mottling could be due to markings on a smooth surface, if the crust is composed of nitrogen, carbon monoxide, or methane ice, since they are soft at the same temperature. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA02212: Triton sur le site de la NASA.PIA00329: Color Sequence of Triton Approach Images
Triton Voyager 2 approach sequence with latitude-longitude grid superposed. The color image was reconstructed by making a computer composite of three black and white images taken through red, green, and blue filters. Details on Triton's surface unfold dramatically in this sequence of approach images. South Pole near the bottom of the images at the convergence of lines of longitude. Resolution changes from about 60 km/pixel (37 mi/pixel) in the image at upper left taken from a distance of 500,000 (311,000 mi) to about 5 km/pixel (3.1 mi/pixel) for the image at lower right. Global and regional albedo features are visible in all of the images. The albedo features can be tracked in successive images and show that Triton has undergone about 3/4 of a rotation during the 4.3-day interval over which these images were obtained. A southern polar cap of bright pink, yellow, and white materials covers nearly all of the southern hemisphere; these materials consist of nitrogen ice with traces of other substances, including frozen methane and carbon monoxide. Feeble ultraviolet radiation from the sun is thought to act on methane to cause chemical reactions to the pinkish yellowish substances. At the time of the Voyager 2 flyby (Jan. 1989) Triton's southern hemisphere was starting the summer season and the South Pole was canted toward the sun day and night, such that the polar cap was sublimating under the relatively 'hot' summer sun (surface temperature about 38 K, about -391 degree F). Numerous dark streaks on the southern polar nitrogen-ice cap are thought to consist of dark dust deposited by prevailing winds in Triton's tenuous nitrogen atmosphere. A bluish band, seen in all of the images, nearly circumstances Triton's equator; this band is thought to consist of fairly nitrogen frost, perhaps deposited in the decade prior to Voyager 2's flyby.
Voir l'image PIA00329: Color Sequence of Triton Approach Images sur le site de la NASA.PIA00060: Triton - False Color of 'Cantaloupe' Terrain
Voyager violet, green, and ultraviolet images of Triton were map projected into cylindrical coordinates and combined to produce this false color terrain map. Several compositionally distinct terrain and geologic features are portrayed. At center is a gray blue unit referred to as 'cantaloupe' terrain because of its unusual topographic texture. The unit appears to predate other units to the left. Immediately adjacent to the cantaloupe terrain, is a smoother unit, represented by a reddish color, that has been dissected by a prominent fault system. This unit apparently overlies a much higher albedo material, seen farther left. A prominent angular albedo boundary separates relatively undisturbed smooth terrain from irregular patches which have been derived from breakup of the same material. Also visible at the far left are diffuse, elongated streaks, which seem to emanate from circular, often bright centered features. The parallel streaks may represent vented particulate materials blown in the same direction by winds in Triton's thin atmosphere. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA00060: Triton - False Color of 'Cantaloupe' Terrain sur le site de la NASA.PIA01994: Triton - Neptune's largest satellite
Already intriguing patterns of unknown origin appear on the surface of Neptune's largest satellite, Triton, in this image returned by Voyager 2. The image was taken Aug. 22, 1989, from a distance of 4 million km (2.5 million miles). Voyager images show that Triton's diameter is about 2,720 kn (1,690 miles), and that it is one of the brightest objects in the solar system, reflecting about 70 percent of the sunlight that strikes it. This is the hemisphere of Triton that always faces away from Neptune. The south pole is near the bottom of the image. Triton's rotation axis is tilted so that the latitude at the center of the disk is 55 degrees south. Dark regions at the top of the disk extend from roughly the equator to beyond 20 degrees north. The margin between the bright and dark regions varies with longitude around the satellite. The gray, featureless area just to the right of the center of the disk is due to a reseau (reticule mark) in the camera. Voyager 2 will make its closest approach to Triton on Aug. 25, when it will pass within 40,000 km (25,000 miles) of the satellite. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA01994: Triton - Neptune's largest satellite sur le site de la NASA.PIA01537: Triton Faults
This image of Triton was taken from a distance of about 130,000 kilometers (80,000 miles) at 12:20 a.m. PDT Aug. 25 1989. The image was received at JPL four hours later at about 4:20 a.m. The smallest detail that can be seen is about 2.5 kilometers (1.5 miles) across. The long linear feature extending vertically across the image is probably a graben (a narrow down dropped fault block) about 35 kilometers (20 miles) across. The ridge in the center of the graben probably is ice that has welled up by plastic flow in the floor of the graben. The surrounding terrain is a relatively young icy surface with few impact craters.
JPL manages the Voyager project for NASA's Office of Space Science.
Voir l'image PIA01537: Triton Faults sur le site de la NASA.
PIA02221: Triton
This photo of Triton is one of a continuing series of "observatory phase" images obtained by the Voyager spacecraft. Lines inscribed on the image at right form a reference grid used by the Imaging Science Team. The Voyager project is managed by the Jet Propulsion Laboratory for the NASA Office of Space Science and Applications.
Voir l'image PIA02221: Triton sur le site de la NASA.
PIA02213: The Limb of Triton
This natural color image of the limb of Triton was taken early in the morning of Aug. 25 1989, when the Voyager 2 spacecraft was at a distance of about 210,000 kilometers (128,000 miles) from the icy satellite. The largest surface features visible area about 3 miles across. The picture is a composite of images taken through the violet, green and clear filters. The image shows a geologic boundary between a rough, pitted surface to the right and a smoother surface to the left. The change between surface types is gradual. The image also shows a color boundary between pinkish material in the upper part of the image and whiter material in the lower part. The geologic and color boundaries are not the same. That implies that whatever supplies the color is avery thin coating over a different underlying material in which the geologic boundary occurs. The colored coating may be a seasonal frost composed of compounds volatile enough to be sublimated at the very low temperatures (40 °K to 50 °K, or -387.4 °F to -369.4 °F) prevailing near Triton's surface. Possible compositions of the frost layer include methane (which turns red when irradiated), carbon monoxide or nitrogen. The color in this image is somewhat exaggerated: Triton is primarily a white object with a pinkish cast in some areas. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA02213: The Limb of Triton sur le site de la NASA.
PIA02214: Triton
This false color image of Triton is a composite of images taken through the violet, green and ultraviolet filters. The image was taken early on Aug. 25, 1989 when Voyager 2 was about 190,000 kilometers (118,000 miles) from Triton's surface. The smallest visible features are about 4 kilometers (2.5 miles) across. The image shows a geologic boundary between completely dark materials and patchy light/dark materials. A layer of pinkish material stretches across the center of the image. The pinkish layer must be thin because underlying albedo patterns show through. Several features appear to be affected by the thin atmosphere; the elongated dark streaks may represent particulate materials blown in the same direction by prevailing winds, and the white material may be frost deposits. Other features appear to be volcanic deposits including the smooth, dark materials alongside the long, narrow canyons. The streaks themselves appear to originate from very small circular sources, some of which are white, like the source of the prominent streak near the center of the image. The sources may be small volcanic vents with fumarolic-like activity. The colors may be due to irradiated methane, which is pink to red, and nitrogen, which is white. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.
Voir l'image PIA02214: Triton sur le site de la NASA.