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  • richardmitnick 10:26 am on December 27, 2018 Permalink | Reply
    Tags: , , , Ceres, , , , What does Ceres’ carbon mean?   

    From EarthSky and SwRI: “What does Ceres’ carbon mean?” 

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    From EarthSky

    December 27, 2018
    Paul Scott Anderson

    Earlier this month, scientists announced that dwarf planet Ceres has more carbon-rich organics than previously thought, both on and below its surface. Here’s why that’s exciting.

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    False-color image of dwarf planet Ceres – largest body in the asteroid belt – from the Dawn spacecraft. The image shows Ceres’ famous bright spots, and the false color highlights differences in surface materials. Image via NASA PhotoJournal.

    Carbon is one of the most common elements in the universe and is the basis of organic biology on Earth. It can be found throughout the solar system, even in meteorites that bounce to Earth’s surface from other parts of space. Now scientists have found that another body in the solar system – the dwarf planet Ceres – is much richer in carbon that previously thought. Those results were published in a peer-reviewed article in Nature Astronomy on December 10, 2018.

    Astronomer Simone Marchi at Southwest Research Institute (SwRI) was the lead author of the new paper. He said:

    “Ceres is like a chemical factory. Among inner solar system bodies, Ceres has a unique mineralogy, which appears to contain up to 20 percent carbon by mass in its near surface. Our analysis shows that carbon-rich compounds are intimately mixed with products of rock-water interactions, such as clays.”

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    The interior structure of Ceres as scientists now understand it. Image via NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

    Why is the presence of carbon so intriguing? Carbon isn’t by itself necessarily the product of or connected to life, although it does serve as the basis for organic chemistry and biology on Earth. When combined with oxygen and hydrogen, carbon can form many groups of important biological compounds including sugars, alcohols and fats. Its presence on Ceres is evidence that the basic ingredients for life – including carbon – can be found in many different places, not only in our solar system but throughout the universe.

    More specifically, the new findings show that Ceres was, and still is, rich in amorphous carbon – a carbon-rich organic material – which is significant in terms of how carbon is distributed throughout the solar system. (Organic materials are any molecules that contain carbon – they can be formed on their own without life but are also building blocks of life). The new data suggests that Ceres contains several times more amorphous carbon on its surface and in its subsurface than even the most carbon-rich meteorites.

    While Ceres contains more carbon than meteorites, the study also shows that 50 to 60 percent of Ceres’ upper crust may have a composition similar to primitive carbonaceous chondrite meteorites – some of the most complex of all meteorites.

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    Close-up view inside Urvara crater on Ceres. The 6,500-foot (1981-meter) central ridge is made from materials uplifted from deep below the surface, which experienced rock-water chemical interactions. Image via NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

    As Marchi explained:

    “Our results imply that either Ceres accreted ultra-carbon-rich materials or that carbon was concentrated in its crust. Both potential scenarios are important, because Ceres’ mineralogical composition indicates a global-scale event of rock-water alteration, which could provide conditions favorable to organic chemistry.”

    In other words, the carbon on Ceres may originate from when Ceres first formed or from incoming impacts of other asteroids. Scientists don’t know yet which scenario is correct. But regardless, the evidence for chemical reactions with water is intriguing, since that can eventually lead to the formation of the building blocks of life, even if not life itself.

    Ceres is classified as a dwarf planet but is also the largest asteroid in the main asteroid belt between Mars and Jupiter. NASA’s Dawn spacecraft recently finished its mission at Ceres on November 1, 2018, studying its geology and sending back incredible high-resolution images of its surface from orbit.

    NASA Dawn Spacescraft

    One big surprise was the “bright spots” – light-colored deposits, now determined to be sodium carbonate salts – on the darker rocky surface. Scientists think they were formed when when water came up to the surface from deeper below and then evaporated in Ceres’ extremely tenuous and sporadic water vapor “atmosphere.”

    The best-known bright spots are those in Occator Crater, which stand out starkly against the darker rocky surface.

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    High-resolution view of Cerealia Facula – a sodium carbonate (salt) deposit – in Occator Crater. Image via NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/Roman Tkachenko.

    Whether Ceres ever had conditions suitable for life to evolve is still unknown, although there is also evidence that it has, or at least once had, water below the surface – maybe even a subsurface ocean. This water produced chemical reactions when it came in contact with minerals in rocks. There is also evidence for past cryovolcanic activity – cryovolcanoes, which erupt water, ammonia or methane rather than molten rock. It’s even possible that the subsurface environment was once warm and wet enough for basic biological chemistry to actually begin, although no direct signs of that have been discovered yet.

    Bottom line: As the largest object in the asteroid belt, Ceres is a fascinating world, and has been more geologically active than previously thought. The fact that Ceres is rich in organic carbon is a big part of its geological history and now scientists are beginning to understand what that means not only for the widespread presence of carbon in the solar system but also how organic chemistry can – at least sometimes – lead to the development of life itself.

    See the full EarthSky article here .

    From SwRI: “SwRI-led team finds evidence for carbon-rich surface on Ceres”

    December 10, 2018

    A team led by Southwest Research Institute has concluded that the surface of dwarf planet Ceres is rich in organic matter. Data from NASA’s Dawn spacecraft indicate that Ceres’ surface may contain several times the concentration of carbon than is present in the most carbon-rich, primitive meteorites found on Earth.

    “Ceres is like a chemical factory,” said SwRI’s Dr. Simone Marchi, a principal scientist who was the lead author of research published in Nature Astronomy today. “Among inner solar system bodies, Ceres has a unique mineralogy, which appears to contain up to 20 percent carbon by mass in its near surface. Our analysis shows that carbon-rich compounds are intimately mixed with products of rock-water interactions, such as clays.”

    Ceres is believed to have originated about 4.6 billion years ago at the dawn of our solar system. Dawn data previously revealed the presence of water and other volatiles, such as ammonium derived from ammonia, and now a high concentration of carbon. This chemistry suggests Ceres formed in a cold environment, perhaps outside the orbit of Jupiter. An ensuing shakeup in the orbits of the large planets would have pushed Ceres to its current location in the main asteroid belt, between the orbits of Mars and Jupiter.

    “With these findings, Ceres has gained a pivotal role in assessing the origin, evolution and distribution of organic species across the inner solar system,” Marchi said. “One has to wonder about how this world may have driven organic chemistry pathways, and how these processes may have affected the make-up of larger planets like the Earth.”

    Geophysical, compositional and collisional models based on Dawn data revealed that Ceres’ partially differentiated interior has been altered by fluid processes. Dawn’s Visible and Infrared Mapping Spectrometer has shown that the overall low albedo of Ceres’ surface is a combination of rock-water interaction products such as phyllosilicates and carbonates and a significant amount of spectrally neutral darkening agents, such as an iron oxide called magnetite.

    Because Dawn’s Gamma Ray and Neutron Detector limits magnetite to only a few percent by mass, the data point to the presence of an additional darkening agent, probably amorphous carbon, a carbon-rich organic material. Interestingly, specific organic compounds have also been detected near a 31-mile-wide impact crater named Ernutet, giving further support to the widespread presence of organics in Ceres’ shallow subsurface.

    The new study also finds that 50-60 percent of Ceres’ upper crust may have a composition similar to primitive carbonaceous chondrite meteorites. This material is compatible with contamination from infalling carbonaceous asteroids, a possibility supported by Ceres’ battered surface.

    “Our results imply that either Ceres accreted ultra-carbon-rich materials or that carbon was concentrated in its crust,” Marchi said. “Both potential scenarios are important, because Ceres’ mineralogical composition indicates a global-scale event of rock-water alteration, which could provide conditions favorable to organic chemistry.”

    The paper “An aqueously altered carbon-rich Ceres” was published on December 10 in Nature Astronomy. The Dawn mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. JPL is responsible for overall Dawn mission science. Northrop Grumman in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.

    For more information visit Planetary Science or contact Deb Schmid, (210) 522-2254, Communications Department, Southwest Research Institute, PO Drawer 28510, San Antonio, TX 78228-0510.

    See the full SwRI article here .


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    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.orgin 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
    • stewarthoughblog 10:35 pm on December 27, 2018 Permalink | Reply

      Some very interesting science here, but “but also how organic chemistry can – at least sometimes – lead to the development of life itself.” is faith based speculation, not objective science. There is no viable evidence that organic chemistry ever formed sufficiently to posit that any serious biochemical compounds ever formed anything remotely complex that could be considered anything relevant to anything living.

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  • richardmitnick 1:47 pm on January 5, 2018 Permalink | Reply
    Tags: , , , , Ceres,   

    From AAS: “The Discovery of Ceres” 


    American Astronomical Society

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    Which is better: to discover a new object in a known category or to discover an entirely new category of objects? This question is at the heart of the ongoing Pluto controversy, but Pluto is far from alone when it comes to being reclassified. Ceres, the largest object in the asteroid belt, has been through this dilemma twice since its discovery; it was demoted from “planet” long before Pluto was even a gleam in any astronomer’s telescope.

    The large, seemingly empty space between the orbits of Mars and Jupiter drew astronomers’ attention dating back to the 1500s and the days of Johannes Kepler and Tycho Brahe. The pattern of these and other planets’ orbits led Kepler to believe that some undiscovered planet must reside there.

    Fast-forward to the 18th century. The Prussian astronomer Johann Titius theorized a relationship between a planet’s distance from the Sun and its sequence in position. His theory essentially states that, in outward sequence, each planet is twice as far from the Sun as the previous one. This law became known as the Titius-Bode law after being popularized by the German astronomer Johann Bode. Aside from a supposedly missing planet between Mars and Jupiter, it described the positions of the then-known planets well — including that of Uranus, not discovered until 1781. A group of astronomers calling themselves the “Celestial Police” turned their telescopes to the yawning gap to find this elusive world.

    On 1 January 1801, with his invitation to join the Celestial Police still in the mail, Giuseppe Piazzi, an Italian priest, mathematician, and astronomer, was looking for a well-known star when he discovered another star-like object moving across the field of his target. Initially thinking it a comet, Piazzi observed it 24 times over the next month and determined from its motion that it might be a planet. In April he sent his complete observations to Paris, and they were published in September. However, due to the object’s position in relation to the Sun, his observations were not verified until December. It was named Ceres, after the Roman goddess of grain. Astronomy textbooks listed it as a planet for the next 50 years.

    From 1800 to 1806, other similar objects were discovered in Ceres’s neighborhood. Astronomers began to wonder if they had, in fact, stumbled across a whole new category of objects. In 1802, William Herschel coined the term “asteroid” to describe them, based on their unresolved, starlike appearance in telescopes. By the 1860s, with the realization that Ceres had several hundred similar neighbors, the distinction between planets and asteroids was widely accepted, although what constitutes a planet was still unclear.

    In 2006 Pluto’s planetary status was under scrutiny, and the IAU more precisely defined a planet’s bona fides. Because Pluto did not make the cut, it became the first of the new category, dwarf planets. Ceres was the second object relegated to dwarf-planet status and remains the only dwarf planet in the asteroid belt. In March 2015, the Dawn spacecraft arrived at Ceres to make NASA’s first visit to a dwarf planet.

    Ultimately, the manner of an object’s classification is linked to scientific advancement and our understanding of the universe. As we have learned more about the objects in our solar system and beyond, astronomers have reclassified Ceres twice, each time making it one of the first of a wholly new category.

    Photo: Approximate true-color image of Ceres. [NASA/ JPL-Caltech / UCLA / MPS / DLR / IDA / Justin Cowart]
    Further Reading [links where available at the full article]:

    Hilton, J. L. 1999 “U.S. Naval Observatory Ephemerides of the Largest Asteroids”. The Astronomical Journal. 117 (2): 1077–1086.
    IAU 2006 “Resolution B5: Definition of a Planet in the Solar System”
    Landau, E., & Dyches, P 2015. “Fly Over Ceres in New Video”. NASA. Retrieved 9 June 2015.
    Herschel, William 1802. “Observations on the two lately discovered celestial Bodies”. Philosophical Transactions of the Royal Society of London. 92: 213–232
    Cunningham, C. J. 2016. “Discovery of The First Asteroid, Ceres”. 1st ed. Springer.
    “Pluto and the Developing Landscape of our Solar System”. 2017. iau.org. https://www.iau.org/public/themes/pluto/

    See the full article here .

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    The American Astronomical Society (AAS) is the major organization of professional astronomers in North America. Our mission is to enhance and share humanity’s scientific understanding of the universe.

     
  • richardmitnick 3:13 pm on July 11, 2017 Permalink | Reply
    Tags: , , , , Ceres, Cornelia crater, , , Haulani Crater, Marcia crater, , Terrain Clues to Ice in the Outer System, The human expansion into the Solar System will demand our being able to identify sources of water, Vesta   

    From Centauri Dreams: “Terrain Clues to Ice in the Outer System” 

    Centauri Dreams

    July 11, 2017
    Paul Gilster

    The human expansion into the Solar System will demand our being able to identify sources of water, a skill we’re honing as explorations continue. On Mars, for example, the study of so-called ‘pitted craters’ has been used as evidence that the low latitude regions of the planet, considered its driest, nonetheless have a layer of underlying ice. The Dawn spacecraft discovered similar pitted terrain on Vesta, as you can see in the image below.

    NASA/Dawn Spacecraft

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    These enhanced-color views from NASA’s Dawn mission show an unusual “pitted terrain” on the floors of the craters named Marcia (left) and Cornelia (right) on the giant asteroid Vesta. The views show that the physical properties or composition of the material in which these pits form is different from crater to crater. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/JHUAPL.

    Vesta’s Marcia crater contains the largest number of pits on the asteroid. The 70-kilometer feature is also one of the youngest craters found there. So what accounts for this kind of terrain? Perhaps the water that formed the pits came from Vesta itself. Another possibility: Low-speed collisions with carbon-rich meteorites could have deposited hydrated materials on the surface, to be released in the heat of subsequent high-speed collisions within the asteroid belt. An explosive degassing into space could explain such pothole-like depressions.

    But Dawn wasn’t through when it left Vesta, and what it has found at Ceres is proving invaluable at understanding what appears to be a common marker of volatile-rich material. In new work from Hanna Sizemore [Geophysical Reseach Letters] (Planetary Science Institute) and colleagues, we learn that Ceres is home to the same kind of pitted terrain. As Sizemore notes:

    “Now, we’ve found this same type of morphological feature on Ceres, and the evidence suggests that ice in the Cerean subsurface dominated the formation of pits there. Finding this type of feature on three different bodies suggests that similar pits might be found on other asteroids we will explore in the future, and that pitted materials may mark the best places to look for ice on those asteroids.”

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    Haulani Crater, Ceres, showing abundant pitted materials on the crater floor. Similar pitted materials have previously been identified on Mars and Vesta, and are associated with rapid volatile release following impact. Their discovery on Ceres indicates pitted materials may be a common morphological indicator of volatile-rich materials in the asteroid belt. Haulani Crater is 34 km in diameter. Color indicates topography. Credit: NASA/MPS/PSI/Thomas Platz.

    Sizemore’s team studied the formation of pitted craters on Ceres through numerical models that explored the role of water ice and other volatiles. The morphological similarities between the Ceres features and what has been found on Mars and Vesta are striking. With water ice evidently significant in pit development on two asteroids and a planet, similar terrains will be of clear interest for future missions in terms of in situ resource utilization.

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    Pitted terrain on Mars as seen by HiRISE aboard the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona.

    Centauri Dreams


    See the full article here .

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    Tracking Research into Deep Space Exploration

    Alpha Centauri and other nearby stars seem impossible destinations not just for manned missions but even for robotic probes like Cassini or Galileo. Nonetheless, serious work on propulsion, communications, long-life electronics and spacecraft autonomy continues at NASA, ESA and many other venues, some in academia, some in private industry. The goal of reaching the stars is a distant one and the work remains low-key, but fascinating ideas continue to emerge. This site will track current research. I’ll also throw in the occasional musing about the literary and cultural implications of interstellar flight. Ultimately, the challenge may be as much philosophical as technological: to reassert the value of the long haul in a time of jittery short-term thinking.

     
  • richardmitnick 8:17 am on April 8, 2017 Permalink | Reply
    Tags: , , , Ceres, Ceres' Temporary Atmosphere Linked to Solar Activity, ,   

    From JPL-Caltech: “Ceres’ Temporary Atmosphere Linked to Solar Activity” 

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    JPL-Caltech

    April 6, 2017
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, CA
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

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    NASA’s Dawn spacecraft determined the hydrogen content of the upper yard, or meter, of Ceres’ surface. Blue indicates where hydrogen content is higher, near the poles, while red indicates lower content at lower latitudes. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

    NASA Dawn Spacescraft

    Scientists have long thought that Ceres may have a very weak, transient atmosphere, but mysteries lingered about its origin and why it’s not always present. Now, researchers suggest that this temporary atmosphere appears to be related to the behavior of the sun, rather than Ceres’ proximity to the sun. The study was conducted by scientists from NASA’s Dawn mission and others who previously identified water vapor at Ceres using other observatories.

    “We think the occurrence of Ceres’ transient atmosphere is the product of solar activity,” said Michaela Villarreal, lead author of the new study in the Astrophysical Journal Letters and researcher at the University of California, Los Angeles.

    Ceres is the largest object in the asteroid belt that lies between Mars and Jupiter. When energetic particles from the sun hit exposed ice and ice near the surface of the dwarf planet, it transfers energy to the water molecules as they collide. This frees the water molecules from the ground, allowing them to escape and create a tenuous atmosphere that may last for a week or so.

    “Our results also have implications for other airless, water-rich bodies of the solar system, including the polar regions of the moon and some asteroids,” said Chris Russell, principal investigator of the Dawn mission, also at UCLA. “Atmospheric releases might be expected from their surfaces, too, when solar activity erupts.”

    Before Dawn arrived in orbit at Ceres in 2015, evidence for an atmosphere had been detected by some observatories at certain times, but not others, suggesting that it is a transient phenomenon. In 1991, the International Ultraviolet Explorer satellite detected hydroxyl emission from Ceres, but not in 1990. Then, in 2007, the European Southern Observatory’s Very Large Telescope searched for a hydroxide emission, but came up empty.

    ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    The European Space Agency’s Herschel Space Observatory detected water in the possible weak atmosphere, or “exosphere,” of Ceres on three occasions, but did not on a fourth attempt.

    ESA/Herschel spacecraft

    As Dawn began its thorough study of Ceres in March 2015, scientists found ample evidence for water in the form of ice. The spacecraft’s gamma ray and neutron detector (GRaND) has found that the uppermost surface is rich in hydrogen, which is consistent with broad expanses of water ice. This ice is nearer to the surface at higher latitudes, where temperatures are lower, a 2016 study published in the journal Science found. Ice has been detected directly at the small bright crater called Oxo and in at least one of the craters that are persistently in shadow in the northern hemisphere. Other research has suggested that persistently shadowed craters are likely to harbor ice. Additionally, the shapes of craters and other features are consistent with significant water-ice content in the crust.

    Because of this evidence for abundant ice, many scientists think that Ceres’ exosphere is created in a process similar to what occurs on comets, even though they are much smaller. In that model, the closer Ceres gets to the sun, the more water vapor is released because of ice sublimating near or at the surface.

    But the new study suggests comet-like behavior may not explain the mix of detections and non-detections of a weak atmosphere.

    “Sublimation probably is present, but we don’t think it’s significant enough to produce the amount of exosphere that we’re seeing,” Villarreal said.

    Villarreal and colleagues showed that past detections of the transient atmosphere coincided with higher concentrations of energetic protons from the sun. Non-detections coincided with lower concentrations of these particles. What’s more, the best detections of Ceres’ atmosphere did not occur at its closest approach to the sun. This suggests that solar activity, rather than Ceres’ proximity to the sun, is a more important factor in generating an exosphere.

    The research began with a 2016 Science study led by Chris Russell. The study, using GRaND data, suggested that, during a six-day period in 2015, Ceres had accelerated electrons from the solar wind to very high energies.

    In its orbital path, Ceres is currently getting closer to the sun. But the sun is now in a particularly quiet period, expected to last for several more years. Since their results indicate Ceres’ exosphere is related to solar activity, study authors are predicting that the dwarf planet will have little to no atmosphere for some time. However, they recommend that other observatories monitor Ceres for future emissions.

    Dawn is now in its extended mission and studying Ceres in a highly elliptical orbit. Engineers are maneuvering the spacecraft to a different orbital plane so that Ceres can be viewed in a new geometry. The primary science objective is to measure cosmic rays to help determine which chemical elements lie near the surface of Ceres. As a bonus, in late April, the sun will be directly behind Dawn, when the spacecraft is at an altitude of about 12,300 miles (20,000 kilometers). Ceres will appear brighter than before in that configuration, and perhaps reveal more secrets about its composition and history.

    The Dawn mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit:

    http://dawn.jpl.nasa.gov/mission

    More information about Dawn is available at the following sites:

    http://www.nasa.gov/dawn

    http://dawn.jpl.nasa.gov

    See the full article here .

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  • richardmitnick 12:41 pm on January 21, 2017 Permalink | Reply
    Tags: Ceres, Interplanetary dust particles (IDPs), , Observations of Ceres indicate that asteroids might be camouflaged, Pyroxene,   

    From SETI: “Observations of Ceres indicate that asteroids might be camouflaged” 

    SETI Logo new
    SETI Institute

    January 18 2017
    Science Contact:

    Franck Marchis
    Email: fmarchis@seti.org

    Media contacts:

    Nicholas A. Veronico
    Email: NVeronico@sofia.usra.edu

    Seth Shostak
    Tel: 650 960-4530
    Email: seth@seti.org

    The appearance of small bodies in the outer solar system could be deceiving. Asteroids and dwarf planets may be camouflaged with an outer layer of material that actually comes from somewhere else.

    Using data primarily gathered by SOFIA, NASA’s Stratospheric Observatory for Infrared Astronomy, a team of astronomers has detected the presence of substantial amounts of material on the surface of Ceres that appears to be fragments of other asteroids.

    NASA/DLR SOFIA
    NASA/DLR SOFIA

    This is contrary to the currently accepted surface composition classification of Ceres, suggesting that the largest body in the asteroid belt between Mars and Jupiter is cloaked by material that has partially disguised its real makeup.

    “We find that the outer few microns of the surface is partially coated with dry particles,” says Franck Marchis, senior planetary astronomer at the SETI Institute. “But they don’t come from Ceres itself. They’re debris from asteroid impacts that probably occurred tens of millions of years ago.”

    Ceres is considered to be both an asteroid and a dwarf planet, the only dwarf planet located in the inner solar system.

    Ceres with bright spot ESO Harps
    Ceres with bright spot ESO Harps

    Astronomers have classified Ceres, as well as 75 percent of all asteroids, as belonging to composition class “C” based on their similar colors. But the mid-infrared spectra from SOFIA show that Ceres differs substantially from C-type asteroids in nearby orbits, challenging the conventional understanding of the relationship between Ceres and smaller asteroids.

    “By analyzing the spectral properties of Ceres we have detected a layer of fine particles of a dry silicate called pyroxene. Models of Ceres based on data collected by NASA’s Dawn…

    NASA/Dawn Spacecraft
    NASA/Dawn Spacecraft

    …as well as ground-based telescopes indicated substantial amounts of water-bearing minerals such as clays and carbonates,” explains Pierre Vernazza, research scientist in the Laboratoire d’Astrophysique de Marseille. “Only the mid-infrared observations made using SOFIA were able to show that both types of material are present on the surface of Ceres.”

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    Ceres’ surface is contaminated by a significant amount of dry material while its the area below the crust contains essentially water-bearing materials. The mid-infrared observations revealed the presence of dry pyroxene on the surface probably coming from interplanetary dust particles. The Internal structure of the Dwarf Planet Ceres was derived from the NASA Dawn spacecraft data. No image credit.

    To identify where the pyroxene on the surface of Ceres came from, Vernazza and his collaborators, including researchers from the SETI Institute and NASA’s Jet Propulsion Laboratory, turned to interplanetary dust particles (IDPs) that are commonly seen as meteors when they streak through Earth’s atmosphere. The research team had previously shown that IDPs blasted into space by asteroid collisions are an important source of material accumulated on the surfaces of other asteroids. The implication is that a coating of IDPs has caused Ceres to mimic the coloration of some of its dry and rocky neighbors.

    Ceres and asteroids are not the only instance in which material transported from elsewhere has affected the surfaces of solar system bodies. Dramatic examples include the red material seen by New Horizons on Pluto’s moon Charon and Saturn’s two-faced moon Iapetus.

    NASA/New Horizons spacecraft
    NASA/New Horizons spacecraft

    Planetary scientists also hypothesize that material from comets and asteroids provided a final veneer to the then-forming Earth – a coating that included substantial amounts of water plus the organic substances of the biosphere.

    This study [The Astronomical Journal] resolves a long standing question about whether surface material accurately reflects the intrinsic composition of an asteroid. These results show that by extending observations to the mid-infrared, one can better identify the composition of an asteroid. According to Vernazza, “the detection of some ammoniated clays mixed with the watery clays on Ceres raises the possibility that the dwarf planet might have formed in the outer reaches of the solar system and somehow migrated to its current location.”

    See the full article here .

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  • richardmitnick 6:14 am on December 16, 2016 Permalink | Reply
    Tags: Ceres, , , Waterworld   

    From Nature: “Solar System’s biggest asteroid is an ancient ocean world” 

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    From JPL-Caltech
    Where is the Ice on Ceres? New NASA Dawn Findings

    News Media Contact
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    Nature Mag
    Nature

    15 December 2016
    Alexandra Witze

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    This graphic shows a theoretical path of a water molecule on Ceres. Some water molecules fall into cold, dark craters at high latitudes called “cold traps,” where very little of the ice turns into vapor, even over the course of a billion years. Other water molecules that do not land in cold traps are lost to space as they hop around the dwarf planet.

    The graphic features an enhanced color image from NASA’s Dawn spacecraft (see PIA20182).

    Asteroids might look dry and barren, but the Solar System’s biggest asteroid — Ceres — is chock full of water, NASA’s Dawn spacecraft has found.

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    This movie of images from NASA’s Dawn spacecraft shows a crater on Ceres that is partly in shadow all the time. Such craters are called “cold traps.” Dawn has shown that water ice could potentially be preserved in such place for very long amounts of time. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    “It’s just oozing,” says Thomas Prettyman, a nuclear engineer at the Planetary Science Institute in Tucson, Arizona. He led the team that built the neutron-counting instrument aboard Dawn, which reported its findings on 15 December in Science.

    NASA Dawn Spacecraft
    NASA Dawn Spacecraft

    Today, the water is either frozen as ice, filling pore spaces deep inside Ceres, or locked inside hydrated minerals at the surface. But billions of years ago, early in Ceres’s history, heat left over from the Solar System’s formation probably kept the asteroid warm inside. This allowed the water to churn and flow, helping to separate Ceres into layers of rock and ice.

    “We know the water and the rock have separated and interacted over time,” said Carol Raymond, a planetary scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, at a meeting of the American Geophysical Union in San Francisco on 15 December.

    The discovery adds to a growing awareness of Ceres as an active, wet world that pushes the boundary of what it means to be a planet. Today it sports a 4-kilometre-high ice volcano and bright spots of salt mixed with ice and rock.

    At 940 kilometres across, Ceres is so big that it contains roughly one-third of all the mass in the asteroid belt — and it is technically both an asteroid and a dwarf planet. Researchers knew that Ceres was rich in water on the basis of its estimated density, by studying light reflecting off the hydrated minerals on its surface and because they spotted water apparently steaming from it. But they did not know exactly how much water was there until Dawn showed up in March 2015.

    Hydrogen highs and lows

    The spacecraft studies chemical elements by counting the gamma-rays and neutrons reflecting off Ceres as cosmic rays bombard it. Prettyman’s team generated a map of the asteroid’s hydrogen, which appears in water ice and hydrated minerals.

    Hydrogen levels were richest in the middle to high latitudes, with the greatest concentrations — up to 30% water — present at the north pole. Around the equator, frozen water has probably sublimated into space and dried out Ceres’s surface, Prettyman says. An astronaut there would have to dig down about 1 metre to find frozen water, whereas at the north pole, a visitor “would just swipe and find the ice table”, he says.

    Ceres’s dampness stands in stark contrast to Vesta, a much drier asteroid visited by Dawn in 2011–12. On average, Ceres is more than 100 times richer in hydrogen than Vesta, Prettyman says.

    A second paper, appearing on 15 December in Nature Astronomy, shows where other frozen water might lie. A team led by Thomas Platz of the Max Planck Institute for Solar System Research in Göttingen, Germany, studied 634 craters on Ceres that are always in the dark. Ten of those have bright areas on the crater floor, and spectral studies of one of them found that it consisted of water ice.

    Similarly to the Moon and Mercury, the airless Ceres apparently manages to trap frozen water in dark areas on its surface, the team says.

    Dawn’s next steps

    Dawn began its extended mission phase in July, and is currently flying in an elliptical orbit more than 4,500 miles (7,200 kilometers) from Ceres. During the primary mission, Dawn orbited and accomplished all of its original objectives at Ceres and protoplanet Vesta, which the spacecraft visited from July 2011 to September 2012.

    Dawn’s mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit:

    http://dawn.jpl.nasa.gov/mission

    More information about Dawn is available at the following sites:

    http://dawn.jpl.nasa.gov

    http://www.nasa.gov/dawn

    See the full Nature article here .
    See the JPL-Caltech article here .

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    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

     
  • richardmitnick 7:38 am on October 15, 2016 Permalink | Reply
    Tags: , , , Ceres, , Mike Brown   

    From Caltech Astronomer Mike Brown: “How many dwarf planets are there in the outer solar system? (updates daily)” 

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    1

    Mike Brown

    How many dwarf planets are there in the outer solar system? (updates daily)
    (As of 1 Nov 2013 also includes latest thermal and occultation results)
    As of Sat Oct 15 2016
    there are:
    10 objects which are nearly certainly dwarf planets,
    30 objects which are highly likely to be dwarf planets,
    75 objects which are likely to be dwarf planets,
    147 objects which are probably dwarf planets, and
    695 objects which are possibly dwarf planets.

    In 2006, when the vote on the definition of “planet” was made, and the eight dominant bodies in the solar system were declared (quite rationally) a class separate from the others, a new class of objects was defined. The “dwarf planets” are all of those objects which are not one of the eight dominant bodies (Mercury through Neptune) yet still, at least in one way, resemble a planet. In other words, a dwarf planet is something that looks like a planet, but is not a planet. Specifically this means that dwarf planets are bodies in the solar system which are large enough to become round due to their own gravitational attraction.

    Why do astronomers care about round? If you place a boulder in space it will just stay whatever irregular shape it is. If you add more boulders to it you can still have an irregular pile. But if you add enough boulders to the pile they will eventually pull themselves into a round shape. This transition from irregularly shaped to round objects is important in the solar system, and, in some ways, marks the transition from an object without and with interesting geological and planetary processes occuring (there are many many other transitions that are equally important, however, a fact that tends to be overlooked in these discussions).

    How many dwarf planets are there? Ceres is the only asteroid that is known to be round.

    2
    Ceres

    After that it gets complicated. All of the rest of the new dwarf planets are in the distant region of the Kuiper belt, where we can’t actually see them well enough to know for sure if they are round or not.

    Kuiper Belt. Minor Planet Center
    Kuiper Belt. Minor Planet Center

    While we can’t see most of the objects in the Kuiper belt well enough to determine whether they are round or not, we can estimate how big an object has to be before it becomes round and therefore how many objects in the Kuiper belt are likely round. In the asteroid belt Ceres, with a diameter of 900 km, is the only object large enough to be round, so somewhere around 900 km is a good cutoff for rocky bodies like asteroids. Most Kuiper belt objects have a lot of ice in their interiors, though. Ice is not as hard as rock, so it less easily withstands the force of gravity, and it takes less force to make an ice ball round. The best estimate for how big an icy body needs to be to become round comes from looking at icy satellites of the giant planets. The smallest body that is generally round is Saturn’s satellite Mimas, which has a diameter of about 400 km.

    4
    Mimas

    Several satellites which have diameters around 200 km are not round. So somewhere between 200 and 400 km an icy body becomes round. Objects with more ice will become round at smaller sizes while those with less rock might be bigger. We will take 400 km as a reasonable lower limit and assume that anything larger than 400 km in the Kuiper belt is round, and thus a dwarf planet.

    How many objects do we know in the Kuiper belt that are 400 km or larger? That question is harder to answer, because we don’t actually know how big most of the objects in the Kuiper belt are. While we can see how bright there are, we don’t know if they are bright because they are larger or are highly reflective. In the past, we had to just throw our hands up in the air and say we don’t know enough to even make reasonable guesses. But in the past few years, systematic measurements of the sizes of objects from the Spitzer Space Telescope and now the Herschel Space Telescope have taught us enought that we can make some reasonable estimates of how reflective objects are.

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    ESA/Herschel
    ESA/Herschel

    (It’s complicated: read the details here ) These reasonable estimates, combined with all available actually measurements, give us the list of the largest Kuiper belt objects, sorted by diameter, below. Carefully note the lack of any error bars. Every single measurement or estimate below is uncertain to some extent or another. I don’t include the individual uncertainties in the table, but instead use the ensemble uncertainties to inform classification below. In other words: take the sizes of specific objects with bigger or smaller grains of salt.

    See the full article here .

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    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

     
  • richardmitnick 12:04 pm on August 31, 2016 Permalink | Reply
    Tags: , , Ceres, ,   

    From JPL-Caltech: “Dawn Sets Course for Higher Orbit” 

    NASA JPL Banner

    JPL-Caltech

    August 31, 2016
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1
    This artist concept shows NASA’s Dawn spacecraft above dwarf planet Ceres, as seen in images from the mission. NASA/JPL-Caltech

    After studying Ceres for more than eight months from its low-altitude science orbit, NASA’s Dawn spacecraft will move higher up for different views of the dwarf planet.

    Dawn has delivered a wealth of images and other data from its current perch at 240 miles (385 kilometers) above Ceres’ surface, which is closer to the dwarf planet than the International Space Station is to Earth. Now, the mission team is pivoting to consider science questions that can be examined from higher up.

    After Dawn completed its prime mission on June 30, having surpassed all of its scientific objectives at Vesta and at Ceres, NASA extended the mission to perform new studies of Ceres. One of the factors limiting Dawn’s lifetime is the amount of hydrazine, the propellant needed to orient the spacecraft to observe Ceres and communicate with Earth. By going to a higher orbit at Ceres, Dawn will use the remaining hydrazine more sparingly, because it won’t have to work as hard to counter Ceres’ gravitational pull.

    “Most spacecraft wouldn’t be able to change their orbital altitude so easily. But thanks to Dawn’s uniquely capable ion propulsion system, we can maneuver the ship to get the greatest scientific return from the mission,” said Marc Rayman, chief engineer and mission director, based at NASA’s Jet Propulsion Laboratory, Pasadena, California.

    On Sept. 2, Dawn will begin spiraling upward to about 910 miles (1,460 kilometers) from Ceres. The altitude will be close to where Dawn was a year ago, but the orientation of the spacecraft’s orbit — specifically, the angle between the orbit plane and the sun — will be different this time, so the spacecraft will have a different view of the surface.

    The mission team is continuing to develop the extended mission itinerary and will submit a full plan to NASA next month.

    Dawn’s mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit:

    http://dawn.jpl.nasa.gov/mission

    More information about Dawn is available at the following sites:

    http://dawn.jpl.nasa.gov

    See the full article here .

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    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 5:43 pm on December 9, 2015 Permalink | Reply
    Tags: , , Ceres,   

    From JPL-Caltech: “New Clues to Ceres’ Bright Spots and Origins” 

    JPL-Caltech

    8 December 2015
    Elizabeth Landau
    NASA’s Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    Elizabeth.Landau@jpl.nasa.gov

    1
    This representation of Ceres’ Occator Crater in false colors shows differences in the surface composition. Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    Ceres reveals some of its well-kept secrets in two new studies in the journal Nature, thanks to data from NASA’s Dawn spacecraft.

    NASA Dawn Spacescraft
    Dawn

    They include highly anticipated insights about mysterious bright features found all over the dwarf planet’s surface.

    In one study, scientists identify this bright material as a kind of salt. The second study suggests the detection of ammonia-rich clays, raising questions about how Ceres formed.

    About the Bright Spots

    Ceres has more than 130 bright areas, and most of them are associated with impact craters. Study authors, led by Andreas Nathues at Max Planck Institute for Solar System Research, Gottingen, Germany, write that the bright material is consistent with a type of magnesium sulfate called hexahydrite. A different type of magnesium sulfate is familiar on Earth as Epsom salt.

    Nathues and colleagues, using images from Dawn’s framing camera, suggest that these 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, they say.

    “The global nature of Ceres’ bright spots suggests that this world has a subsurface layer that contains briny water-ice,” Nathues said.

    A New Look at Occator

    The surface of Ceres, whose average diameter is 584 miles (940 kilometers), is generally dark — similar in brightness to fresh asphalt — study authors wrote. The bright patches that pepper the surface represent a large range of brightness, with the brightest areas reflecting about 50 percent of sunlight shining on the area. But there has not been unambiguous detection of water ice on Ceres; higher-resolution data are needed to settle this question.

    The inner portion of a crater called Occator contains the brightest material on Ceres. Occator itself is 60 miles (90 kilometers) in diameter, and its central pit, covered by this bright material, measures about 6 miles (10 kilometers) wide and 0.3 miles (0.5 kilometers) deep. Dark streaks, possibly fractures, traverse the pit. Remnants of a central peak, which was up to 0.3 miles (0.5 kilometers) high, can also be seen.

    With its sharp rim and walls, and abundant terraces and landslide deposits, Occator appears to be among the youngest features on Ceres. Dawn mission scientists estimate its age to be about 78 million years old.

    Study authors write that some views of Occator appear to show a diffuse haze near the surface that fills the floor of the crater. This may be associated with observations of water vapor at Ceres by the Herschel space observatory that were reported in 2014. The haze seems to be present in views during noon, local time, and absent at dawn and dusk, study authors write. This suggests that the phenomenon resembles the activity at the surface of a comet, with water vapor lifting tiny particles of dust and residual ice. Future data and analysis may test this hypothesis and reveal clues about the process causing this activity.

    “The Dawn science team is still discussing these results and analyzing data to better understand what is happening at Occator,” said Chris Russell, principal investigator of the Dawn mission, based at the University of California, Los Angeles.

    The Importance of Ammonia

    In the second Nature study, members of the Dawn science team examined the composition of Ceres and found evidence for ammonia-rich clays. They used data from the visible and infrared mapping spectrometer, a device that looks at how various wavelengths of light are reflected by the surface, allowing minerals to be identified.

    Ammonia ice by itself would evaporate on Ceres today, because the dwarf planet is too warm. However, ammonia molecules could be stable if present in combination with (i.e. chemically bonded to) other minerals.

    The presence of ammoniated compounds raises the 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. Another idea is that Ceres formed close to its present position, incorporating materials that drifted in from the outer solar system – near the orbit of Neptune, where nitrogen ices are thermally stable.

    “The presence of ammonia-bearing species suggests that Ceres is composed of material accreted in an environment where ammonia and nitrogen were abundant. Consequently, we think that this material originated in the outer cold solar system,” said Maria Cristina De Sanctis, lead author of the study, based at the National Institute of Astrophysics, Rome.

    In comparing the spectrum of reflected light from Ceres to meteorites, scientists found some similarities. Specifically, they focused on the spectra, or chemical fingerprints, of carbonaceous chondrites, a type of carbon-rich meteorite thought to be relevant analogues for the dwarf planet. But these are not good matches for all wavelengths that the instrument sampled, the team found. In particular, there were distinctive absorption bands, matching mixtures containing ammoniated minerals, associated with wavelengths that can’t be observed from Earth-based telescopes.

    The scientists note another difference is that these carbonaceous chondrites have bulk water contents of 15 to 20 percent, while Ceres’ content is as much as 30 percent.

    “Ceres may have retained more volatiles than these meteorites, or it could have accreted the water from volatile-rich material,” De Sanctis said.

    The study also shows that daytime surface temperatures on Ceres span from minus 136 degrees to minus 28 degrees Fahrenheit (180 to 240 Kelvin). The maximum temperatures were measured in the equatorial region. The temperatures at and near the equator are generally too high to support ice at the surface for a long time, study authors say, but data from Dawn’s next orbit will reveal more details.

    As of this week, Dawn has reached its final orbital altitude at Ceres, about 240 miles (385 kilometers) from the surface of the dwarf planet. In mid-December, Dawn will begin taking observations from this orbit, including images at a resolution of 120 feet (35 meters) per pixel, infrared, gamma ray and neutron spectra, and high-resolution gravity data.

    Dawn’s mission is managed by the Jet Propulsion Laboratory for NASA. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.

    For a complete list of mission participants, visit:

    http://dawn.jpl.nasa.gov/mission

    More information about Dawn is available at the following sites:

    http://dawn.jpl.nasa.gov

    http://www.nasa.gov/dawn

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 4:59 pm on September 30, 2015 Permalink | Reply
    Tags: , , Ceres,   

    From JPL: “Dawn Team Shares New Maps and Insights about Ceres” 

    JPL

    Sept. 30, 2015
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1
    This map-projected view of Ceres was created from images taken by NASA’s Dawn spacecraft during its high-altitude mapping orbit, in August and September, 2015.
    Images taken using infrared (920 nanometers), red (750 nanometers) and blue (440 nanometers) spectral filters were combined to create this false-color view. Redder colors indicate places on Ceres’ surface that reflect light strongly in the infrared, while bluish colors indicate enhanced reflectivity at short (bluer) wavelengths; green indicates places where albedo, or overall brightness, is strongly enhanced.
    Scientists use this technique in order to highlight subtle color differences across Ceres, which would appear fairly uniform in natural color. This can provide valuable insights into the mineral composition of the surface, as well as the relative ages of surface features.
    For a complete list of acknowledgments, see http://dawn.jpl.nasa.gov/mission.

    Mysteries and insights about Ceres are being discussed this week at the European Planetary Science Conference in Nantes, France. NASA’s Dawn spacecraft is providing scientists with tantalizing views and other data about the intriguing dwarf planet that they continue to analyze.

    NASA Dawn Spacescraft
    Dawn

    “Ceres continues to amaze, yet puzzle us, as we examine our multitude of images, spectra and now energetic particle bursts,” said Chris Russell, Dawn principal investigator at the University of California, Los Angeles.

    2
    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. Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    A new color-coded topographic map shows more than a dozen recently approved names for features on Ceres, 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-kilometer) diameter mountain near Ceres’ north pole is now called Ysolo Mons, for an Albanian festival that marks the first day of the eggplant harvest.

    3
    This view, made using images taken by NASA’s Dawn spacecraft, is a color-coded topographic map of Occator crater on Ceres.
    Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    Another new Ceres map, in false color, enhances compositional differences present on the surface. The variations are more subtle than on Vesta, Dawn’s previous port of call. Color-coded topographic images of Occator (oh-KAH-tor) crater, home of Ceres’ brightest spots, and a puzzling, cone-shaped 4-mile-high (6-kilometer-high) mountain, are also available. Scientists are still trying to identify processes that could produce these and other unique Cerean phenomena.

    “The irregular shapes of craters on Ceres are especially interesting, resembling craters we see on Saturn’s icy moon Rhea,” said Carol Raymond, Dawn’s deputy principal investigator based at NASA’s Jet Propulsion Laboratory, Pasadena, California. “They are very different from the bowl-shaped craters on Vesta.”

    A surprising bonus observation came from Dawn’s gamma ray and neutron spectrometer. The instrument 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.

    “This is a very unexpected observation for which we are now testing hypotheses,” Russell said.

    Dawn is currently orbiting Ceres at an altitude of 915 miles (1,470 kilometers), and the spacecraft will image the entire surface of the dwarf planet up to six times in this phase of the mission. Each imaging cycle takes 11 days.

    Starting in October and continuing into December, Dawn will descend to its lowest and final orbit, an altitude of 230 miles (375 kilometers). The spacecraft will continue imaging Ceres and taking other data at higher resolutions than ever before at this last orbit. It will remain operational at least through mid-2016.

    Dawn made history as the first mission to reach a dwarf planet, and the first to orbit two distinct extraterrestrial targets, when it arrived at Ceres on March 6, 2015. It conducted extensive observations of Vesta in 2011 and 2012.

    Dawn’s mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit:

    http://dawn.jpl.nasa.gov/mission

    More information about Dawn is available at the following sites:

    http://dawn.jpl.nasa.gov

    http://www.nasa.gov/dawn

    See the full article here .

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    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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