DAWN Results Returned From Ceres

NASA's Dawn spacecraft has become the first mission to achieve orbit around a dwarf planet, Ceres. It was captured by the dwarf planet’s gravity at about 4:39 a.m. PST (7:39 a.m. EST) Friday, March 6th 2015

Data Related to DAWN Capture Into Ceres Orbit Data Dated mid-2015 Data Dated 2016 Data Dated 2017 Data Dated 2018

Data Related to DAWN Capture Into Ceres Orbit

NASA's Dawn spacecraft has become the first mission to achieve orbit around a dwarf planet. The spacecraft was approximately 38,000 miles (61,000 kilometers) from Ceres when it was captured by the dwarf planet’s gravity at about 4:39 a.m. PST (7:39 a.m. EST) Friday, March 6th 2015. Mission controllers at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. received a signal from the spacecraft at 5:36 a.m. PST (8:36 a.m. EST) that Dawn was healthy and thrusting with its ion engine, the indicator Dawn had entered orbit as planned. DAWN was approaching at a speed of 450 mph (725 km/) and kept spiraling into to be captured into orbit. As it reached Ceres, DAWN turned the first mission to orbit two extraterrestrial targets, which are the two most massive residents of our solar system’s Asteroid belt! The final approach phase began by December 2014 as approach operations were to begin in late January 2015 as first images of the minor planet began to be possible since February 2015 for navigation purposes as a first picture had been taken on Dec. 5, 2014 as part of the calibration process, from a distance of 740,000 miles (1.2 million km). Next ops were that DAWN was to be captured by Ceres' gravity on March 6th, 2015. A first full characterization of Ceres will be following at a altitude of about 8,400 miles (13,500 kilometers), then a spiral down bringing the craft to a altitude of about 2,750 miles (4,430 kilometers) for more data from that survey science orbit. That phase is scheduled to last during 22 days for mapping. DAWN will then continue to spiral its way down to a altitude of about 920 miles (1,480 kilometers), and in August 2015 it will begin a two-month phase known as the 'high-altitude mapping orbit.' After, further, a spiraling down DAWN will begin its closest orbit around Ceres in late November 2015, at a distance of about 233 miles (375 kilometers) and during three month, for low-altitude mapping and data through the gamma ray and neutron detector (GRaND) and gravity investigation. Ceres is named for the Roman goddess of agriculture and harvests. Craters on Ceres will similarly be named for gods and goddesses of agriculture and vegetation from world mythology. Other features will be named for agricultural festivals

	As first views of Ceres have shown a landscape pummeled with craters. Observations performed from the Earth by early 2014 also showed that Ceres features water and dust and that its icy mantle was once a watery subterranean ocean, as such liquid may remain even today. Geysers or icy volcanoes, or cryovolcanism, might play a role in the dwarf planet’s activity. Water appears might make up about 40 percent of Ceres' volume, making the asteroid the largest water reservoir in the inner solar system other than the Earth. picture courtesy site 'Amateur Astronomy' from pictures NASA
	Differences in morphology and color across the surface with that color map suggest Ceres was once an active body. Ceres' surface is heavily cratered, as expected, but appears to have fewer large craters than scientists anticipated. It also has a pair of very bright neighboring spots in its northern hemisphere. Planetary scientists have identified 10 bright regions on Ceres’ surface. picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
	North pole of dwarf planet Ceres as seen by the DAWN spacecraft on April 10, 2015 at a distance of 21,000 miles (33,000 kilometers) after spending more than a month in orbit around the minor planet. picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Data Dated mid-2015

NASA's DAWN spacecraft fired up its ion engine on Oct. 23, 2015 to begin its journey toward its fourth and final science orbit at dwarf planet Ceres. The spacecraft completed two months of observations from an altitude of 915 miles (1,470 kilometers) and transmitted extensive imagery and other data to Earth. The spacecraft is now on its way to the final orbit of the mission, called the low-altitude mapping orbit. Dawn will spend more than seven weeks descending to this vantage point, which will be less than 235 miles (380 kilometers) from the surface of Ceres. In mid-December, Dawn will begin taking observations from this orbit, including images at a resolution of 120 feet (35 meters) per pixel

	That view of Ceres was taken on May 23, 2015, from a distance of 3,200 miles (5,100 kilometers) at a resolution about 1,600 feet (480 meters) per pixel. Numerous secondary craters, formed by the re-impact of debris, have been strewn along. picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
	A region of areas with a bright albedo is found inside a crater about 55 miles (90 kilometers) across as it is constituted of numerous bright points, with a central cluster. It is possible that that region be made of water ice. picture courtesy NASA
	Miscellaneous terrain at Ceres. picture courtesy NASA
	A area of cratered terrain at Ceres. DAWN, on a other hand, also detected three bursts of energetic electrons that may result from the interaction between Ceres and radiation from the Sun. The observation isn't yet fully understood, but may be important in forming a complete picture of Ceres. picture courtesy NASA
	Central pits in large craters are much more common than at other solar system's bodies. Also seen are evidence of past activity on the surface, including flows, landslides and collapsed structures altogether with more bright spots. picture courtesy NASA
	This color-coded map from NASA's Dawn mission shows the highs and lows of topography on the surface of dwarf planet Ceres. It is labeled with names of features approved by the International Astronomical Union. All approved names for features on Ceres are all eponymous for agricultural spirits, deities and festivals from cultures around the world. These include Jaja, after the Abkhazian harvest goddess, and Ernutet, after the cobra-headed Egyptian harvest goddess. A 12-mile (20-km) diameter mountain near Ceres' north pole is now called Ysolo Mons, for an Albanian festival that marks the first day of the eggplant harvest. Height differences between craters' bottom and mountain peaks are as great as 9 miles (15km). Irregular shapes of craters on Ceres are especially interesting, resembling craters on Saturn's moon Rhea as they are very different from the bowl-shaped craters on Vesta. In terms of depth and diameter, and density, they are very similar to those of Dione and Tethys. picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
	Intriguing brightest spots on Ceres lie in a crater named Occator, which is about 60 miles (90 kilometers) across and 2 miles (4 kilometers) deep. picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/LPI
	No explanation until now was released for such a mountainous feature seen in the southern hemisphere of Ceres, as it further lies close to a crater! Ahuna Mons is best described as a dome with smooth, steep walls as it has a lot of bright material on some of its slopes, and less on others. On its steepest side, it is about 3-miles (5-kilometer) high. picture site 'Amateur Astronomy' based upon pictur courtesy NASA
	Here is the Gaue crater, the larger crater seen here. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
	A new view of Ocator crater reveals better-defined shapes of the brightest, central spot and features on the crater floor as the current orbit of DAWN allows to a three times better resolution than previous. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech

Bright areas at craters at Ceres have been found consistent with a type of magnesium sulfate called hexahydrite, or being deposits -- called faculae -- of carbonates and other salts. A different type of magnesium sulfate is familiar on Earth as Epsom salt. Such salt-rich areas were left behind when water-ice sublimated in the past. Impacts from asteroids would have unearthed the mixture of ice and salt, hinting to Ceres having a subsurface layer that contains briny water-ice. As there has not been unambiguous detection of water ice on Ceres, higher-resolution data are needed to settle that question. As far as the youngest Occator crater bright areas are concerned, when sunlight reaches Ceres' Occator Crater, a kind of thin haze of dust and evaporating water forms there. The haze seems to be present in views during noon, local time, and absent at dawn and dusk, suggesting that the phenomenon resembles the activity at the surface of a comet. The DAWN science team also found evidence for ammonia-rich clays, raising he possibility that Ceres did not originate in the main asteroid belt between Mars and Jupiter, where it currently resides, but instead might have formed in the outer solar system, or, whether it formed at its current position, it incorporated materials that drifted in from the outer solar system – near the orbit of Neptune, where nitrogen ices are thermally stable. The environment where Ceres formed had to feature abundant ammonia and nitrogen as Ceres-carbonaceous chondrites is not a good match. The minor planet, generally, shares many commonalities with meteorites however, in particular carbonaceous chondrites. Ammonia ice by itself would evaporate on Ceres today, because the dwarf planet is too warm as ammonia molecules could be stable if present if chemically bonded to other minerals. The brightest area of the Occator Crater has the highest concentration of carbonate minerals ever seen outside Earth. At about 80 million years old, Occator is considered a young crater. The impact that formed the crater millions of years ago unearthed material that blanketed the area outside the crater, and may have triggered the upwelling of salty liquid. Carbonates are found at Earth in hydrothermal environments. If one exists inside the crater, that would suggest that temperatures inside Ceres are warmer than previously believed. More intriguingly, liquid water may have existed beneath the surface of Ceres in recent geological time. The salts thus could be remnants of an ocean, or localized bodies of water, that reached the surface and then froze millions of years ago. The surface of Ceres, generally, contains ammoniated phyllosilicates, or clays containing ammonia. Because ammonia is abundant in the outer solar system, this finding introduced the idea that Ceres may have formed near the orbit of Neptune and migrated inward. Alternatively, Ceres may have formed closer to its current position between Mars and Jupiter, but with material accumulated from the outer solar system. The carbonate finding further reinforces Ceres' connection with icy worlds in the outer solar system. Such materials might also make Ceres interesting for the study of astrobiology. Most of Ceres' largest craters are more than 1 mile (2 kilometers) deep relative to surrounding terrain, meaning they have not deformed much over billions of years. These significant depths suggest that Ceres' subsurface is no more than 40 percent ice by volume, and the rest may be a mixture of rock and low-density materials such as salts or chemical compounds called clathrates. The appearance of a few shallow craters suggests that there could be variations in ice and rock content in the subsurface. Daytime surface temperatures on Ceres, on a other hand, span from minus 136 degrees to minus 28 degrees Fahrenheit (180 to 240 Kelvin) as maximum temperatures were measured in the equatorial region

NASA's DAWN spacecraft, cruising in its lowest and final orbit at dwarf planet Ceres, by a altitude of 240 miles (385 kilometers), has delivered images showcasing details of the minor planet's cratered and fractured surface at a resolution of about 120 feet (35 meters) per pixel. As troughs are common on larger planetary bodies, because of contraction, impact stresses and the loading of the crust by large mountains, fracturing found all across Ceres' surface indicates that similar processes may have occurred there, despite its smaller size. Many of the troughs and grooves on Ceres were likely formed as a result of impacts, but some appear to be tectonic, reflecting internal stresses that broke the crust. picture site 'Amateur Astronomy' based upon pictures courtesy NASA

Data Dated 2016

DAWN will remain at its lowest altitude for the rest of its mission, and indefinitely afterward. The end of the prime mission will be June 30, 2016. Ceres is a heavily cratered body with diverse features on its surface that include a tall, cone-shaped mountain -the Ahuna Mons- and more than 130 reflective patches of material that is likely salt. Scientists believe areas with shades of blue contain younger, fresher material, including flows, pits and cracks. By 2006, the International Astronomical Union upgraded Ceres from asteroid to dwarf planet, receiving the same classification as Pluto. Depuis 2013 one knew that there is water vapor emanating from Ceres, following up on 1992 observations of hydroxide by NASA's International Ultraviolet Explorer. to learn more, not only about Ceres itself but also about the dawn of the solar system. Vesta and Ceres are intact, which means that the spatial relationships of their surface features and internal layers are preserved

	This image from NASA's Dawn spacecraft shows Kupalo Crater, one of the youngest craters on Ceres. The crater has bright material exposed on its rim and walls, which could be salts. Its flat floor likely formed from impact melt and debris. It measures 16 miles (26 kilometers) across. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
	This image from NASA's Dawn spacecraft shows, right, part of Messor Crater (25 miles or 40 kilometers, wide), located at northern mid-latitudes on Ceres. The scene shows an older crater in which a large lobe-shaped flow partly covers the northern (top left) part of the crater floor. The flow is a mass of material ejected when a younger crater formed just north of the rim. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
	The fractured floor of 78-mile-wide (126-kilometer-wide) Dantu Crater on Ceres is seen in this image. Similar fractures are seen in Tycho, one of the youngest large craters on our Moon. This cracking may have resulted from the cooling of impact melt, or when the crater floor was uplifted after the crater formed. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
	NASA's Dawn spacecraft viewed this 20-mile (32-kilometer) Cerean crater, which is covered in ridges and steep slopes, called scarps on Dec. 23, 2015. These features likely resulted when the crater partly collapsed during its formation. The curvilinear nature of the scarps resembles those on the floor of Rheasilvia, the giant impact crater on Vesta, which Dawn orbited from 2011 to 2012. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Ceres does not have as many large impact basins as scientists expected as impact processes dominate the surface geology however. Increased hydrogen concentration has been spotted at high latitudes, a hint to that water ice could be present close to the surface in polar regions as it would have subterraneanly survived for billions of years. Ice could exist also a the Oxo Crater like bound up in minerals or the form of ice. Bright spots in Haulani Crater are showing that material excavated by an impact is different than the general surface composition of Ceres. The diversity of materials implies either that there is a mixed layer underneath, or that the impact itself changed the properties of the materials. Impact craters are clearly the most abundant geological feature on Ceres, and their different shapes help tell the intricate story of Ceres' past. Craters that are roughly polygonal hint that Ceres' crust is heavily fractured. Their straight edges result from pre-existing stress patterns and faults beneath the surface. In addition, several Cerean craters have patterns of visible fractures on their floors, others may have endured landslides and others still are seen with fresh material impact. Fractures, generally, may play a role in driving the geometry of some of Ceres' craters. Some, like tiny Oxo, have terraces, while others, such as the large Urvara Crater (106-mile (170-kilometer) wide), have central peaks. There are craters with flow-like features, and craters that imprint on other craters, as well as chains of small craters. Bright areas are peppered across Ceres, with the most reflective ones in Occator Crater. Some crater shapes could indicate water-ice in the subsurface. Such miscellaneous crater forms are consistent with an outer shell for Ceres that is not purely ice or rock, but rather a mixture of both, and not uniform. Based upon the ratio of various craters' depths to diameters, some amount of crater relaxation must have occurred. Additionally, there are more craters in the northern hemisphere of Ceres than the south, where the large Urvara and Yalode craters are the dominant features. Clay-forming minerals called phyllosilicates are all over Ceres, and rich in magnesium and also have some ammonium embedded in their crystalline structure. Their distribution throughout the dwarf planet's crust indicates Ceres' surface material has been altered by a global process involving water. Phyllosilicates are especially prevalent in the region around the smooth crater Kerwan (174 miles, 280 kilometers in diameter), and less so at Yalode Crater (162 miles, 260 kilometers in diameter), which has areas of both smooth and rugged terrain around it. Craters Dantu and Haulani both formed recently in geologic time, but also seem to differ in composition. Different material mixtures thus could extend beneath the surface. Ceres, generally, is covered by countless small, young craters, but none are larger than 175 miles (280 kilometers). Somehow thus, Ceres eroded its largest impact scars as it also renewed old, cratered surfaces through activies like hydrothermal activity or cryovolcanism. Three large-scale depressions, or 'planitiae' at Ceres, up to 500-mile (800-kilometer) wide could be leftovers from big impacts. Ceres's largest well-defined impact basin is Kerwan Crater. Even if Ceres would have formed in the vicinity of Neptune and then migrated inwards, it should still have kept a significant number of large craters. The obliteration of large craters must have occurred over several hundred millions of years. Like a comparison, although Vesta is only half the size of Ceres, it has a well-preserved 300-mile-(500-kilometer)-wide crater called Rheasilvia, with other large craters that suggests that Vesta did not have processes at work to smooth its surface, perhaps because it is thought to have much less ice. Bright spots at Ceres brighten during the day and also show other variations, suggesting that the observed changes could be due to the presence of volatile substances that evaporate under the action of solar radiation. Permanently shadowed regions at Ceres are extent like at Mercury or the Moon. When the temperature stays below about minus 240 degrees Fahrenheit (minus 151 degrees Celsius), the area is termed a 'cold trap.' Such regions at Ceres might be more numerous because the minor planet is more far away from the Sun as cold traps might extend to relatively lower latitudes, at the difference of Mercury or Moon with those areas at the poles only. Ceres, on a other hand, may have been formed with a relatively large reservoir of water providing for such remnants. The upper layers of Ceres contain ice -- and maybe salt -- bringing the topography above to smooth out. Salt could be the remnant of a frozen ocean under the surface, and liquid water could have been present in Ceres' interior. Evidence was found of the chemistry of an ancient ocean. The findings reinforce the idea that dwarf planets, not just icy moons like Enceladus and Europa, could have hosted oceans during their history, and potentially still do. Analyses from Dawn data suggest there still may be liquid under Ceres’ surface and that some regions were geologically active relatively recently, feeding from a deep reservoir. Ceres may have a weak, temporary atmosphere, which would be consistent with the water vapor detected at Ceres in 2012-2013. The temporary atmosphere of Ceres -- a exosphere indeed -- appears to be related to the behavior of the Sun, rather than Ceres' proximity to it like scientists had thought, in a comparison to the sublimation process at comets when they come nearer to the Sun. It is the solar wind which hit exposed ice or near the surface which frees water molecules from there and create a tenuous atmosphere that may last for a week or so. Ice is nearer to surface at high latitudes. Ceres could have formed beyond Jupiter and migrated in, or at least incorporated materials that originated farther from the Sun

Gravitational data gathered from the orbit suggest that Ceres is a differentiated body, with compositionally distinct layers at different depths, with the densest layer at the core. Low-density materials such as water ice, separated from the rocky material and rose to the outer layer. Ceres internal structure is less defined generally as high-elevation areas on Ceres displace mass in the interior. In the past, Ceres' interior did not heat up to the temperatures at which silicates melt and a metallic core forms and ice water interacted with rocks. Ceres is much less dense than other rocky bodies in our solar system. Ceres, on a other hand, has a special property called 'hydrostatic equilibrium,' as its interior is weak enough that its shape is governed by how it rotates. Ceres' hydrostatic equilibrium is one reason why astronomers classified the body as a dwarf planet in 2006. The top layer of Ceres was found by early 2017 to contain anhydrous (dry) pyroxene dust accumulated from space mixed in with native hydrous (wet) dust, carbonates, and water ice. Which hints to that the carbon-rich surface surface composition of the minor planet could have been cloaked by rocky silicates from fragments of other asteroids. That might question the C classification of Ceres. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Ahuna Mons on Ceres was likely formed as a salty-mud cryovolcano -- a unique feature in the solar system -- showing that volcanism exists on a dwarf planet made of salts, muddy rocks and water ice. Ahuna Mons might be due to a plume extending from Ceres mantle, carrying slurry upwared as the dome might have been created just a couple hundred million years ago. Ahuna Mons formed within the last billion years, and possibly within a few hundred million years. Exposed water-ice is rare on Ceres, but the low density of Ceres, the impact-generated flows and the very existence of Ahuna Mons suggest that Ceres' crust does contain a significant component of water-ice. Studies from Dawn scientists by late 2016 show evidence for ice at or near the surface of Ceres. Ice might have separated from rock early in Ceres' history, forming a ice-rich crustal layer, which remained since near the surface. That layer is closer to the surface at higher latitudes. Rather than a solid ice layer, there is likely to be a porous mixture of rocky materials in which ice fills the pores, at 10 percent. Ceres thus would have been divided into a rocky interior and icy outer shell, the energy being the radioactive decay of materials deep inside. Water ice would also lie in ice-trap dark craters near to the poles like for Moon or Mercury. A tenuous water atmosphere at Ceres however might be at the origin of cold traps at Ceres however, with water molecules moving from lower to higher latitudes

Ahuna Mons seen in that mosaic of images has a height, on its steepest side, of about 3 miles (5 kilometers). Its average overall height is of 2.5 miles (4 kilometers) with a diameter about 12 miles (20 kilometers). picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL/Dawn mission

Dawn scientists have released that image of Ceres that approximates how the dwarf planet's colors would appear to the human eye. The view, produced by the German Aerospace Center in Berlin, combines images taken from Dawn's first science orbit in 2015, through red, green and blue filters. The color was calculated based on the way Ceres reflects different wavelengths of light. picture site 'Amateur Astronomy' based upon a picture courtesy NASA

DAWN, by early 2017, detected organic material -- those molecules which are necessary though not sufficient components of life -- on Ceres, in and around a northern-hemisphere crater called Ernutet, making Ceres a further body in the solar system harbouring organics. Those molecules might be native to Ceres. There is growing evidence that the organics in Ernutet came from Ceres’ interior, in which case they could have existed for some time in the early, interior ocean. Minor planet Ceres was already known to feature hydrated minerals, carbonates, water ice, and ammoniated clays that must have been altered by water and warmth as salts and sodium carbonate, like found in the Occator Crater, are also thought to have been carried to the surface by liquid. Material of similar composition has been found at Oxo Crater and Ahuna Mons. Sodium carbonate might be linked to a briny liquid likely spurted up from Ceres' interior, which delivered this salt to the surface. Ceres is mostly covered in phyllosilicates -- tiny rock particles typically found in mud on Earth. Across Ceres' surface, DAWN found a type of mineral that has ammonium (a compound derived from ammonia) incorporated into its structure. Scientists were astounded, as substances containing ammonia are not expected in bodies that formed as close to the Sun as Ceres' orbit. The result suggested that Ceres could have formed beyond Jupiter and migrated inward, or that it has materials that originated farther from the Sun incorporated into its surface. Ceres also might have undergone different types or degrees of alteration by water. Ceres organics might also have been processed in a warm water-rich environment

That enhanced color composite image is showing the area around Ernutet Crater on Ceres, where organic materials exist. Pink areas are rich in organics as green less. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/ASI/INAF

Data Dated 2017

The bright central area of Ceres' Occator Crater, as it was named Cerealia Facula, at about 4 million years old, is approximately 30 million years younger than the crater itself. The secondary, smaller bright areas of Occator, called Vinalia Faculae, are comprised of a mixture of carbonates and dark material. The initial trigger to the bright area was the impact that dug out the crater itself, causing briny liquid to rise closer to the surface. Water and dissolved gases, such as carbon dioxide and methane, came up and created a vent system. These rising gases also could have forced carbonate-rich materials to ascend toward the surface and erupting through fractures. DAWN, as of early March 2017, was on its way to a high-altitude orbit of 12,400 miles (20,000 kilometers), and to a different orbital plane. Jupiter and Saturn have a appreciable effect on Ceres' axial tilt, which varies over the course of about 24,500 years, influencing the water deposits found at the minor planet's poles. Throughout the last 3 million years, Ceres has gone through cycles where its tilt ranges from about 2 to about 20 degrees. It might that since more than 4 billion years, most of a Ceres' ancient ocean is now frozen and bound up in the crust, remaining in the form of ice, clathrate hydrates and salts, as a easily deformable layer beneath Ceres' rigid surface crust could be the signature of residual liquid left over from the ocean too (that latter characteristic allowed that pronounced surface features at Ceres smoothed out over time). It is still unknown why Ceres' crust be as light as ice in terms of density, but simultaneously much stronger. Ahuna Mons and the Occator crater are believed to be different expressions of cryovolcanism, and associated with gravity anomalies. Surface features on Ceres have a closer relationship with its interior evolution, as pit chains linear features, for example, are due to that less dense materials beneath Ceres' surface pushed upward toward the exterior hundreds of millions (up to a billion) years ago, creating fractures in the crust. Such features are not evenly dispersed across. The more than 300 of bright, reflective areas or 'faculae,' that stand out at Ceres' surface are a hint that the dwarf planet once had a subsurface ocean the salty liquid of which upwelled materials to the surface. Such bright material is found at various terrain features. The bright material in Occator Crater is made of salt-rich material and would resemble dirty snow to the human eye. Occator might have had in recent times a reservoir of salty water beneath it which flowed like lava, or percolated material upwards through crevaces resulting from the impact. In the second category, bright material is found on the rims of craters, streaking down toward the floors as impacting bodies likely exposed bright material that was already in the subsurface. Bright material may also be found in craters' ejecta as mountain Ahuna Mons gets its own fourth category as unaffiliated with any impact crater, and likely a cryovolcano

A significant amount of water ice at Ceres is also induced from landslides found. There are three types of them, the type I found at high latitudes where the most ice is thought to reside just beneath the surface. Type II features are the most common type and often thinner. Type III landslides might involve a brief melting of some of the ice within the soil-like regolith, causing the material to flow like mud before refreezing, and always associated with large impact craters. The ice in the upper few tens of yards (meters) of Ceres, generally, may range from 10 to 50 percent by volume. picture site 'Amateur Astronomy' based upon a picture courtesy NASA

To the right of the northeastern rim of Urvara Crater, which is at lower left, the long, narrow feature that appears to jut out toward North is called Pongal Catena, at about 60 miles (96 km) long. Catenae may result from a series of impact craters, or represent large faults created by internal forces, like the case here. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Juling Crater seen here is 1.6-mile deep with many features indicative of the flow of material suggesting the subsurface is rich in ice. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

This false-color image of Ceres highlights differences in surface materials and reveals a dichotomy, and the elaborate composition of Ceres' crust. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

This orthographic projection, centered on Occator Crater, shows a image of Ceres obtained from a low-altitude mapping orbit. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Cerealia Facula in the center (at 6-mile-wide (10-kilometer-wide)) and Vinalia Faculae to the side are the bright material found on Occator Crater's floor as that fine image is a one with a simulated perspective view. Occator Crater is 57-mile-wide (92-kilometer-wide). picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

This image shows a complex set of fractures found on the floor of Occator Crater on Ceres (North is at the top). Such fractures have been interpreted as evidence that material came up from below and formed a dome shape, or is ice freezing below. picture site 'Amateur Astronomy' based upon a picture courtesy NASA

That map is showing locations of bright material, or 'faculae,' on dwarf planet Ceres. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI/Caltech

Kwanzaa Tholus, a small mountain about 22 by 12 miles (35 by 19 kilometers) and about 2-mile (3-km) high is seen on that picture like a small crescent-shaped shadow stands out, at the center right. Tholus are small mountain with a typical rounded shape as Kwanzaa Tholust was likely as prominent as cryovolcano Ahuna Mons as ice, which is not strong enough to preserve an elevated structure for extended periods, gradually collapsed over tens of millions of years. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Data Dated 2018

The great diversity of material, ice and carbonates, exposed via impacts, landslides and cryovolcanism suggests Ceres’ crust is not uniform in composition. These heterogeneities were either produced during the freezing of Ceres’ original ocean -- which formed the crust -- or later on as a consequence of large impacts or cryovolcanic intrusions, which brings to Ceres a dynamic body. Hydrated carbonate dehydrate over a few million years as seasonal changes release water vapor which then condenses into water ice. Detected water vapour was detected around the dwarf planet as Ceres has ice on or near its surface. The contribution of the ice deposits to Ceres' exosphere turned out to be much lower than thought

The floor of Juling Crater, a crater 12 mile-wide, shows evidence of a flow of ice and rock, similar to rock glaciers in Earth’s polar regions. The crater's northern wall also holds water ice which is caused by seasonal changes which release water vapor. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/ASI/INAF

Hanami Planum is the third largest geological feature on Ceres, extending over 345 miles (555 kilometers) as it also features Occator Crater (to the upper left). Several parallel linear features, called Junina Catenae, can be seen departing from Occator. These catenae are chains of small craters formed by the impact and scouring of material ejected when large craters are formed. Junina Catenae are related to Urvara and Yalode crater located far away, in the southern hemisphere as some of their ejecta could reach the northern hemisphere thanks to Ceres' fast rotation and small size. picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

The recent low orbit of DAWN, by mid-2018, has revealed unprecedented details of the relationships between sodium carbonate-made bright and dark materials in the region of Vinalia Faculae in Occator Crater. That view was obtained from a altitude of about 24 miles (39 kilometers) only! picture site 'Amateur Astronomy' based upon a picture courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Another view of Cerealia Facula, at 19.7 degrees north latitude and 239.6 degrees south longitude picture site 'Amateur Astronomy' based upon a picture courtesy NASA