User:Marshallsumter/Rocks/Rocky objects/Ceres

Ceres appears to be a rocky object and an astronomical object. It is a radiated object now in an orbit around the Sun well within one light year radius.

Astronomy
The image on the right was taken by NASA's Dawn spacecraft on May 5 and 6, 2015, from a distance of 8,400 miles (13,600 kilometers).

Planetary sciences
The Gamma Ray and Neutron Detector (GRaND) onboard the Dawn spacecraft is based on similar instruments flown on the Lunar Prospector and Mars Odyssey space missions. It will be used to measure the abundances of the major rock-forming elements (oxygen, magnesium, aluminium, silicon, calcium, titanium, and iron) on Vesta and Ceres, as well as potassium, thorium, uranium, and water (inferred from hydrogen content).

"Ceres rotates in this sped-up movie [on the right] comprised of images taken by NASA's Dawn mission during its approach to the dwarf planet. The images were taken on Feb. 19, 2015, from a distance of nearly 29,000 miles (46,000 kilometers). Dawn observed Ceres for a full rotation of the dwarf planet, which lasts about nine hours. The images have a resolution of 2.5 miles (4 kilometers) per pixel."

Theoretical Ceres astronomy
Def. "a celestial body that

(a) is in orbit around the Sun,

(b) has sufficient mass for its self-gravity to overcome rigid forces so that it assumes a hydrostatic equilibrium (nearly round) shape,

(c) has not cleared the neighbourhood around its orbit, and

(d) is not a satellite" is called a dwarf planet.

"Ceres is the smallest identified dwarf planet in the solar system.

"Observations of 1 Ceres, the largest known asteroid, have revealed that the object may be a "mini planet," and may contain large amounts of pure water ice beneath its surface."

"The observations by NASA's Hubble Space Telescope also show that Ceres shares characteristics of the rocky, terrestrial planets like Earth. Ceres' shape is almost round like Earth's, suggesting that the asteroid may have a "differentiated interior," with a rocky inner core and a thin, dusty outer crust."

"Observations of 1 Ceres, the largest known asteroid, have revealed that the object may be a "mini planet," and may contain large amounts of pure water ice beneath its surface."

"The observations by NASA's Hubble Space Telescope also show that Ceres shares characteristics of the rocky, terrestrial planets like Earth. Ceres' shape is almost round like Earth's, suggesting that the asteroid may have a "differentiated interior," with a rocky inner core and a thin, dusty outer crust."

"Ceres is an embryonic planet. Gravitational perturbations from Jupiter billions of years ago prevented Ceres from accreting more material to become a full-fledged planet."

"Hubble snapped 267 images of Ceres. From those snapshots, the astronomers determined that the asteroid has a nearly round body. The diameter at its equator is wider than at its poles. Computer models show that a nearly round object like Ceres has a differentiated interior, with denser material at the core and lighter minerals near the surface. All terrestrial planets have differentiated interiors. Asteroids much smaller than Ceres have not been found to have such interiors."

"Computer models [such as the image on the right] show that a nearly round object like Ceres has a differentiated interior, with denser material at the core and lighter minerals near the surface. All terrestrial planets have differentiated interiors. Asteroids much smaller than Ceres have not been found to have such interiors."

"The astronomers suspect that water ice may be buried under the asteroid's crust because the density of Ceres is less than that of the Earth's crust, and because the surface bears spectral evidence of water-bearing minerals. They estimate that if Ceres were composed of 25 percent water, it may have more water than all the fresh water on Earth. Ceres' water, unlike Earth's, would be in the form of water ice and located in the mantle, which wraps around the asteroid's solid core."

The second image down on the right, an artist's concept, "summarizes our understanding of how the inside of Ceres could be structured, based on the data returned by the NASA's Dawn mission."

"Using information about Ceres' gravity and topography, scientists found that Ceres is "differentiated," which means that it has compositionally distinct layers at different depths. The most internal layer, the "mantle" is dominated by hydrated rocks, like clays. The external layer, the 24.85-mile (40-kilometer) thick crust, is a mixture of ice, salts, and hydrated minerals. Between the two is a layer that may contain a little bit of liquid rich in salts, called brine. It extends down at least 62 miles (100 kilometers). The Dawn observations cannot "see" below about 62 miles (100 kilometers) in depth. Hence, it is not possible to tell if Ceres' deep interior contains more liquid or a core of dense material rich in metal."

Planetary astronomy
"The diagram illustrates the orbits of Ceres (blue) and several planets (white/grey). The segments of orbits below the ecliptic are plotted in darker colours, and the orange plus sign is the Sun's location. The top left diagram is a polar view that shows the location of Ceres in the gap between Mars and Jupiter. The top right is a close-up demonstrating the locations of the perihelia (q) and aphelia (Q) of Ceres and Mars. Interestingly, the perihelia of Ceres (as well as those of several other of the largest MBAs) and Mars are on the opposite sides of the Sun. The bottom diagram is a perspective view showing the inclination of the orbit of Ceres compared to the orbits of Mars and Jupiter."

The animation shows the relative location of the orbit of Ceres.

Neutrons
"This map [on the right] shows a portion of the northern hemisphere of Ceres with neutron counting data acquired by the gamma ray and neutron detector (GRaND) instrument aboard NASA's Dawn spacecraft."

"These data reflect the concentration of hydrogen in the upper yard (or meter) of regolith, the loose surface material on Ceres. The color information is based on the number of neutrons detected per second by GRaND. Counts decrease with increasing hydrogen concentration. The color scale of the map is from blue (lowest neutron count) to red (highest neutron count)."

"Lower neutron counts near the pole suggest the presence of water ice within about a yard (meter) of the surface at high latitudes."

"The GRaND data were acquired from Dawn's low-altitude mapping orbit (LAMO) at Ceres, a distance of 240 miles (385 kilometers) from the dwarf planet. The longitude is centered on Occator Crater."

Ultraviolets
High-resolution ultraviolet Hubble Space Telescope images taken in 1995 showed a dark spot on its surface which was nicknamed "Piazzi" in honour of the discoverer of Ceres. This was thought to be a crater. Later near-infrared images with a higher resolution taken over a whole rotation with the Keck telescope using adaptive optics showed several bright and dark features moving with the dwarf planet's rotation.

Visuals
"This approximately true-color image was taken at 15:27 on May 7, 2015, as Dawn was surveying Ceres in its "Rotation Characterization 3" orbit 13,583 kilometers above the surface. At the terminator, near the top, is Urvara, a large crater with radiating troughs. Closer to the center of the disk is the large Yalode basin, with its flat floor and faint inner ring. Farther down the terminator is the large Mondamin crater. Haulani crater makes a bright splash near the lower right edge of the disk. The cone-shaped Ahuna mons is near center."

Reds
"Over five hours of observations 15 spectra of asteroid [Ceres] with step 2.46 nm in the region 336 - 746 nm were obtained to see whether the spectral characteristics of the Ceres surface changed with the rotation phase. On processing the observational material, it turned out that the spectra of the asteroid are unusually red (i.e., a remarkable rise of relative reflection coefficients with wave length growth occurs)."

Asteroids
Ceres is the only dwarf planet in the asteroid belt.

"Ceres is approximately 580 miles (930 kilometers) across, about the size of Texas. It resides with tens of thousands of other asteroids in the main asteroid belt. Located between Mars and Jupiter, the asteroid belt probably represents primitive pieces of the solar system that never managed to accumulate into a genuine planet. Ceres comprises 25 percent of the asteroid belt's total mass. However, Pluto, our solar system's smallest planet, is 14 times more massive than Ceres."

"The astronomers used Hubble's Advanced Camera for Surveys to study Ceres for nine hours, the time it takes the asteroid to complete a rotation. Hubble snapped 267 images of Ceres. From those snapshots, the astronomers determined that the asteroid has a nearly round body. The diameter at its equator is wider than at its poles."

G asteroids
G-type asteroids are a relatively uncommon type of carbonaceous asteroid. The most notable asteroid in this class is 1 Ceres. Generally similar to the C-type objects, but containing a strong ultraviolet absorption feature below 0.5 μm.

Ceres has been classified both as a C-type asteroid and, due to the presence of clay minerals, as a G-type asteroid. Its composition is similar, though not identical, to those of carbonaceous chondrite meteorites. Ceres has a mean diameter of 939.4 km and a mass of $9.39 kg$ as determined from the Dawn spacecraft. This gives it a density of $2.162 g/cm3$, suggesting up to a quarter of its mass is composed of water. Ceres is an oblate spheroid, with an equatorial diameter eight percent larger than its polar diameter.

Asteroid belts
Def. a "region of the orbital plane of the solar system located between the orbits of Mars and Jupiter which is occupied by numerous minor planets and the dwarf planet Ceres" is called an asteroid belt.

"The MB group is the most numerous group of MCs. ... 50 % of the MB Mars-crossers [MCs] become ECs within 59.9 Myr and [this] contribution ... dominates the production of ECs". MB denotes the main belt of asteroids.

The interplanetary medium includes interplanetary dust, cosmic rays and hot plasma from the solar wind. The temperature of the interplanetary medium varies. For dust particles within the asteroid belt, typical temperatures range from 200 K (−73 °C) at 2.2 AU down to 165 K (−108 °C) at 3.2 AU The density of the interplanetary medium is very low, about 5 particles per cubic centimeter in the vicinity of the Earth; it decreases with increasing distance from the sun, in inverse proportion to the square of the distance. It is variable, and may be affected by magnetic fields and events such as coronal mass ejections. It may rise to as high as 100 particles/cm³.

"The hydromagnetic approach led to the discovery of two important observational regularities in the solar system: (1) the band structure [such as in the rings of Saturn and in the asteroid belt], and (2) the cosmogonic shadow effect (the two-thirds fall down effect)."

The majority of known asteroids orbit within the asteroid belt between the orbits of Mars and Jupiter. This belt is now estimated to contain between 1.1 and 1.9 million asteroids larger than 1 km in diameter. and millions of smaller ones.

Craters
"The 6-mile-wide (10-kilometer-wide) crater named Oxo Crater is the second-brightest feature on Ceres. Only Occator's central area is brighter. Oxo lies near the 0 degree meridian that defines the edge of many Ceres maps, making this small feature easy to overlook. NASA Dawn spacecraft took this image in its low-altitude mapping orbit, at a distance of 240 miles (385 kilometers) from the surface of Ceres."

"Oxo is also unique because of the relatively large "slump" in its crater rim, where a mass of material has dropped below the surface. Dawn science team members are also examining the signatures of minerals on the crater floor, which appear different than elsewhere on Ceres."

"The image has been rotated so that north on Ceres is up."

"A variety of craters [Urvara and Yalode on the right] and other geological features can be found on dwarf planet Ceres. NASA's Dawn spacecraft took this image of Ceres from an altitude of 2,700 miles (4,400 kilometers). The image, with a resolution of 1,400 feet (410 meters) per pixel, was taken on June 5, 2015."

"The bright spots [on the left in Occator crater] are much brighter than the rest of Ceres' surface, and tend to appear overexposed in most images. This view is a composite of two images of Occator: one using a short exposure that captures the detail in the bright spots, and one where the background surface is captured at normal exposure."

"The images were obtained by Dawn during the mission's High Altitude Mapping Orbit (HAMO) phase, from which the spacecraft imaged the surface at a resolution of about 450 feet (140 meters) per pixel."

"The view [second down on the left] was produced by combining the highest resolution images of Occator obtained in February 2016 (at image scales of 35 meters, or 115 feet, per pixel) with color images obtained in September 2015 (at image scales of 135 meters, or about 440 feet, per pixel). The three images used to produce the color were taken using spectral filters centered at 438, 550 and 965 nanometers (the latter being slightly beyond the range of human vision, in the near-infrared)."

"The crater measures 57 miles (92 kilometers) across and 2.5 miles (4 kilometers) deep. Dawn's close-up view reveals a dome in a smooth-walled pit in the bright center of the crater. Numerous linear features and fractures crisscross the top and flanks of this dome."

Volcanoes
The "views [such as the one on the right] were made using images taken by NASA's Dawn spacecraft during its low-altitude mapping orbit, at a distance of about 240 miles (385 kilometers) from the surface. The resolution of the component images is about 120 feet (35 meters) per pixel."

"Elevations span a range of about 5.5 miles (9 kilometers) from the lowest places in the region to the highest terrains. Blue represents the lowest elevation, and brown is the highest. The streaks running down the side of the mountain, which appear white in the grayscale view, are especially bright parts of the surface (the brightness does not relate to elevation). The elevations are from a shape model generated using images taken at varying sun and viewing angles during Dawn's lower-resolution, high-altitude mapping orbit (HAMO) phase."

"The prominent mountain Ahuna Mons on Ceres [in the image on the left] has been interpreted as a cryovolcanic construct5. Ahuna Mons has an upper age limit of 240 million years (Myr) derived from crater size–frequency analysis of units that it superposes5, but it may be much younger because the mountain itself is too small and has too few craters to be reliably dated."

"Sodium carbonates are present on the flanks of Ahuna Mons and are consistent with a cryo-volcanic origin13,17."

Topography
"This pair of images shows color-coded maps from NASA's Dawn mission, revealing the highs and lows of topography on the surface of dwarf planet Ceres."

"The map at left is centered on terrain at 60 degrees east longitude; the map at right is centered on 240 degrees east longitude."

"The color scale extends about 5 miles (7.5 kilometers) below the surface in indigo to 5 miles (7.5 kilometers) above the surface in white."

"The topographic map was constructed from analyzing images from Dawn's framing camera taken from varying sun and viewing angles. The map was combined with an image mosaic of Ceres and projected as an orthographic projection."

"The well-known bright spots in the center of Ceres northern hemisphere in the image at right retain their bright appearance, although they are color-coded in the same green elevation of the crater floor in which they sit."

"Note: The elevation scale used for this topographic map product differs slightly from the scale used to create PIA19605."

The second image down on the right shows a topographic map with the larger features named.

"This topographical map of Ceres, made with images from NASA's Dawn spacecraft, shows all of the dwarf planet's named features as of September 2016. Dawn celebrated nine years since launch on September 27, 2016."

"To date, more than 110 places on Ceres have been named. These include craters such as Occator Crater, home of the brightest areas on the dwarf planet, as well as crater chains called catenae, mountains such as Ahuna Mons, and other geological features."

"Among the most recently named features is Kwanzaa Tholus, named after the African-American winter holiday Kwanzaa, which is based on ancient African harvest festivals. A tholus is a small dome-shaped mountain or hill. There are a total of seven tholi named on Ceres."

The two images on the right are the two poles of Ceres.

"Researchers from NASA's Dawn mission have composed the first comprehensive views of the north (left) and south pole regions (right) of dwarf planet Ceres, using images obtained by the Dawn spacecraft. The images were taken between Aug. 17 and Oct. 23, 2015, from an altitude of 915 miles (1,470 kilometers)."

"The region around the south pole appears black in this view because this area has been in shade ever since Dawn's arrival on March 6, 2015, and is therefore not visible."

"At the north polar region, craters Jarovit, Ghanan and Asari are visible, as well as the mountain Ysolo Mons. Near the south pole, craters Attis and Zadeni can be seen."

"Detailed maps of the polar regions allow researchers to study the craters in this area and compare them to those covering other parts of Ceres. Variations in shape and complexity can point to different surface compositions. In addition, the bottoms of some craters located close to the poles receive no sunlight throughout Ceres' orbit around the sun. Scientists want to investigate whether surface ice can be found there."

Carbons
Tholins, formed from ultraviolet irradiation of simple carbon compounds, were detected on Ceres in Ernutet crater, and most of the planet's surface is extremely rich in carbon, with approximately 20% carbon by mass in its near surface. The carbon content is more than five times higher than in carbonaceous chondrite meteorites analyzed on Earth. The surface carbon shows evidence of being mixed with products of rock-water interactions, such as clays. This chemistry suggests Ceres formed in a cold environment, perhaps outside the orbit of Jupiter, and that it accreted from ultra-carbon-rich materials in the presence of water, which could provide conditions favorable to organic chemistry.

Recent history
The recent history period dates from around 1,000 b2k to present.

When Ceres has an opposition near the perihelion, it can reach a visual magnitude of +6.7. This is generally regarded as too dim to be seen with the naked eye, but under exceptional viewing conditions a very sharp-sighted person may be able to see this dwarf planet.

"Besides being the largest asteroid, Ceres also was the first asteroid to be discovered. Sicilian astronomer Father Giuseppe Piazzi spotted the object in 1801. Piazzi was looking for suspected planets in a large gap between the orbits of Mars and Jupiter. As more such objects were found in the same region, they became known as "asteroids" or "minor planets.""

Hypotheses

 * 1) Ceres is another cratered surface, rocky object.