C. M. Pieters's research while affiliated with Brown University and other places

Publications (866)

Article
The Moon is generally depleted in volatile elements and this depletion extends to the surface where the most abundant mineral, anorthite, features <6 ppm H2O. Presumably the other nominally anhydrous minerals that dominate the mineral composition of the global surface—olivine and pyroxene—are similarly depleted in water and other volatiles. Thus th...
Article
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Plain Language Summary The outermost meter of dwarf planet Ceres contains water ice that is gradually sublimating in response to heating of the surface by sunlight. Since Ceres' axis of rotation is nearly perpendicular to the Sun's rays, ice has receded to greater depths at the equator than the poles. The distribution of subsurface ice within this...
Preprint
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Understanding the origin and evolution of the lunar volatile system is not only compelling lunar science, but also fundamental Solar System science. This white paper (submitted to the US National Academies' Decadal Survey in Planetary Science and Astrobiology 2023-2032) summarizes recent advances in our understanding of lunar volatiles, identifies...
Conference Paper
Volatile sources for the poles vary in space and time. Now, meteorites and solar wind dominate the inputs; in the past volcanic eruptions and impacts overwhelmed the current sources. Major gaps in understanding persist regarding all epochs.
Article
Combined analyses of the surface elemental composition and mineralogy of Vesta and Ceres provide insights into their interior evolution, crustal formation, and regolith processes. Compositional data acquired by Dawn's Visible to Infrared Mapping Spectrometer (VIR) and Gamma Ray and Neutron Detector (GRaND) are sensitive to different depths and spat...
Article
We investigate the region of crater Haulani on Ceres with an emphasis on mineralogy as inferred from data obtained by Dawn's Visible InfraRed mapping spectrometer (VIR), combined with multispectral image products from the Dawn Framing Camera (FC) so as to enable a clear correlation with specific geologic features. Haulani, which is one of the young...
Article
Using Moon Mineralogy Mapper data, we characterize surface diversity across the enormous South Pole - Aitken Basin (SPA) by evaluating the abundance and composition of pyroxenes, which are overwhelmingly the most abundant mafic mineral in the region. Although SPA exhibits significant complexity due to billions of years of geologic processes subsequ...
Article
The geologic context of red organic-rich materials (ROR) found across an elongated 200 km region on Ceres is evaluated with spectral information from the multispectral framing camera (FC) and the visible and near-infrared mapping spectrometer (VIR) of Dawn. Discrete areas of ROR materials are found to be associated with small fresh craters less tha...
Article
The objective of this study is to explore the regional geology of the northwest Imbrium region in which the Chang'E-3 (CE-3) landing site is located. CE-3 successfully landed on December 14, 2013 on the unsampled Eratosthenian basalts whose study is important for understanding the evolution of the Moon. New geologic and structural maps of the resea...
Article
Phobos and Deimos are the only natural satellites of the terrestrial planets, other than our Moon. Despite decades of revolutionary Mars exploration and plans to send humans to the surface of Mars in the 2030's, there are many strategic knowledge gaps regarding the moons of Mars, specifically regarding the origin and evolution of these bodies. Addr...
Article
With the help of a new observing technique, we have detected diurnal variations in both lunar albedo protons and incident galactic cosmic rays (GCRs) at the Moon. Using the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument on the Lunar Reconnaissance Orbiter (LRO), we have combined specific, targeted observations of the lunar ho...
Article
Ceres has been explored by NASA/Dawn spacecraft, which allowed for the discovery of the main mineralogical and compositional characteristics of Ceres' surface. Here, we use mainly data from the Visible and InfraRed imaging spectrometer (VIR) in order to investigate the main spectral characteristics of the quadrangle Ac-H-2 Coniraya, one of the 15 q...
Article
The dwarf planet Ceres has been explored by NASA's Dawn spacecraft with the goal of characterizing its geology, mineralogy, topography, shape, and internal structure. One outcome of this exploration is the production of geologic maps, meant to unveil the geologic history of Ceres. In this paper, we present the geologic map of the Ac-6 Haulani quadr...
Article
Ac-H-6 'Haulani' is one of five quadrangles that cover the equatorial region of the dwarf planet Ceres. This quadrangle is notable for the broad, spectrally distinct ejecta that originate from the crater Haulani, which gives the name to the quadrangle. These ejecta exhibit one of the most negative ('bluest') visible to near infrared spectral slope...
Article
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The mineralogy and geochemistry of Ceres, as constrained by Dawn's instruments, are broadly consistent with a carbonaceous chondrite (CM/CI) bulk composition. Differences explainable by Ceres’s more advanced alteration include the formation of Mg-rich serpentine and ammoniated clay; a greater proportion of carbonate and lesser organic matter; amoun...
Article
We conducted a geologic mapping investigation of Dawn spacecraft data to determine the geologic history of the Kerwan impact basin region of dwarf planet Ceres, which is mostly located in the Ac-7 Kerwan Quadrangle. Geological mapping was applied to Dawn Framing Camera images from the Low Altitude Mapping Orbit (LAMO, 35[U+202F]m/pixel) and supplem...
Conference Paper
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Introduction: Hansteen alpha, the arrow-head volcanic construct, is one of the red spots on the Moon which have long been suggested to be formed by silicic volcanism [1, 2]. The silicic nature of the red spots (including Hansteen alpha) was confirmed recently based on the Diviner observations [3] onboard Lunar Reconaissance Orbiter (LRO) spacecraft...
Article
Organic compounds occur in some chondritic meteorites, and their signatures on solar system bodies have been sought for decades. Spectral signatures of organics have not been unambiguously identified on the surfaces of asteroids, whereas they have been detected on cometary nuclei. Data returned by the Visible and InfraRed Mapping Spectrometer on bo...
Conference Paper
During the Dawn mission, observations at Ceres reveal numerous interesting post-impact modifications in and around craters. These modifications contain the deposition of extended plains material with pits, multiple lobate flows, and widely dispersed deposits that form a diffuse veneer on the preexisting surface.
Article
Ahuna Mons is the highest mountain on Ceres. A unique complex in terms of size, shape, and morphology, Ahuna is bordered by flanks of the talus around its summit. Recent work by Ruesch et al. [2016] based on Dawn's Framing Camera images shed light on the possible origin of Ahuna Mons. According to Ruesch et al. [2016], Ahuna Mons is formed by a vol...
Article
Craters on Ceres, such as Haulani, Kupalo, Ikapati, and Occator show post-impact modification by the deposition of extended plains material with pits, multiple lobate flows, and widely dispersed deposits that form a diffuse veneer on the preexisting surface. Bright material units in these features have a negative spectral slope in the visible range...
Conference Paper
Ceres, the largest object in the main asteroid belt, and second target of the NASA Dawn mission, was mapped by VIR at different spatial resolutions. Visible and InfraRed (VIR) spectrometer onboard Dawn shed light on the overall surface composition of Ceres. The thermally-corrected average spectrum of Ceres as observed by VIR reveals the presence of...
Conference Paper
On dwarf planet Ceres, several high-albedo units are visible at the local scale. Haulani crater, located in the equatorial quadrangle having the same name, is one of the notable bright units highlighted by the Dawn spacecraft since its first approach to Ceres in early 2015. Due to the images obtained by the Dawn Framing Camera, it was possible to r...
Article
On 6 March 2015, Dawn arrived at Ceres to find a dark, desiccated surface punctuated by small, bright areas. Parts of Ceres' surface are heavily cratered, but the largest expected craters are absent. Ceres appears gravitationally relaxed at only the longest wavelengths, implying a mechanically strong lithosphere with a weaker deep interior. Ceres'...
Article
The dwarf planet Ceres is known to host phyllosilicate minerals at its surface, but their distribution and origin have not previously been determined.We used the spectrometer onboard the Dawn spacecraft to map their spatial distribution on the basis of diagnostic absorption features in the visible and near-infrared spectral range (0.25 to 5.0microm...
Article
Space weathering refers to alteration that occurs in the space environment with time. Lunar samples, and to some extent meteorites, have provided a benchmark for understanding the processes and products of space weathering. Lunar soils are derived principally from local materials but have accumulated a range of optically active opaque particles (OA...
Article
We study the spectrophotometric properties of dwarf planet Ceres in the VIS-IR spectral range by means of hyper-spectral images acquired by the VIR instrument onboard NASA Dawn mission. Observations with phase angle within the $7.3^{\circ}<\alpha<131^{\circ}$ interval have been used to characterize Ceres' phase curve in the 0.465-4.05 $\mu m$ spect...
Conference Paper
Ceres´ surface is affected by numerous impact craters and some of them show features such as channels or multiple flow events forming a smooth, less cratered surface, indicating possible post-impact resurfacing. Flow features occur on several craters on Ceres such as Haulani, Ikapati, Occator, Jarimba and Kondos in combination with smooth crater fl...
Article
The typically dark surface of the dwarf planet Ceres is punctuated by areas of much higher albedo, most prominently in the Occator crater. These small bright areas have been tentatively interpreted as containing a large amount of hydrated magnesium sulfate, in contrast to the average surface, which is a mixture of low-albedo materials and magnesium...
Article
High resolution geological mapping aided by imagery and elevation data from the Lunar Reconnaissance Orbiter (LRO) and Kaguya missions has revealed the scientifically rich character of impact melt deposits at two young complex craters: Jackson (71 km) and Tycho (85 km). The morphology and distribution of mapped impact melt units provide several ins...
Article
Apollo lunar regolith samples are not available in quantity for engineering studies with In-Situ Resource Utilization (ISRU). Therefore, with expectation of a return to the Moon, dozens of regolith (soil) simulants have been developed, to some extent a result of inefficient distribution of NASA-sanctioned simulants. In this paper, we review many of...
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Visible to near-infrared (V-NIR) remote sensing observations have identified spinel in various locations and lithologies on the Moon. Experimental studies have quantified the FeO content of these spinels (Jackson et al. 2014), however the chromite component is not well constrained. Here we present compositional and spectral analyses of spinel synth...
Article
We reexamine the relationship between pyroxene composition and near-infrared absorption bands, integrating measurements of diverse natural and synthetic samples. We test an algorithm (PLC) involving a two-part linear continuum removal and parabolic fits to the 1 and 2 μm bands—a computationally simple approach which can easily be automated and appl...
Conference Paper
Quadrangle Ac-H-6 ‘Haulani’ is one of five quadrangles that cover the equatorial region of the dwarf planet Ceres. This quadrangle is notable for the high albedo (bright) ejecta that extend around crater Haulani, which gives the name to the quadrangle. In Dawn’s Framing Camera (FC) color-ratio composite images, crater Haulani is clearly distinct co...
Conference Paper
In March 2015, the NASA Dawn spacecraft entered orbit around Ceres, the largest object in the main asteroid belt. The Visible and InfraRed (VIR) mapping spectrometer onboard Dawn unveiled the mineralogy of Ceres at unprecedented spatial resolution. The VIR thermally-corrected average spectrum of Ceres revealed the presence of several absorption ban...
Conference Paper
Some craters on Ceres show post-impact modifications, like the deposition of extended plains laced with pits, lobate flows, and ponded material [1]. We found those features on craters with a bluish spectral signature, such as Haulani, Ikapati, Occator and Kupalo. Lobate flows of Haulani and Kupalo originating from the crest of the central ridge [1,...
Conference Paper
Quadrangles Ac-11 and Ac-12 are two of the one of four southern quadrangles of the dwarf planet Ceres. These quadrangles have several craters, notably the large Sintana and Toharu which give the names to the quadrangle. To study the mineralogical composition of this sourthen region we use in particular the data returned by the Visible and InfraRed...
Article
Studies of the dwarf planet (1) Ceres using ground-based and orbiting telescopes have concluded that its closest meteoritic analogues are the volatile-rich CI and CM carbonaceous chondrites. Water in clay minerals, ammoniated phyllosilicates, or a mixture of Mg(OH)2 (brucite), Mg2CO3 and iron-rich serpentine have all been proposed to exist on the s...
Article
The dwarf planet (1) Ceres, the largest object in the main asteroid belt with a mean diameter of about 950 kilometres, is located at a mean distance from the Sun of about 2.8 astronomical units (one astronomical unit is the Earth-Sun distance). Thermal evolution models suggest that it is a differentiated body with potential geological activity. Unl...
Article
We find evidence for hydrated material in the lunar regolith using “albedo protons” measured with the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter (LRO). Fluxes of these albedo protons, which are emitted from the regolith due to steady bombardment by high energy radiation (Galactic Cosmic Rays), are...
Article
“Mafic Mound” is a distinctive and enigmatic feature 75 km across and 1 km high near the center of the vast South Pole-Aitken Basin (SPA). Using several modern data sets, we characterize the composition, morphology, and gravity signature of the structure in order to assess its origin. Mafic Mound is found to exhibit a perched circular depression an...
Article
Exposure to ion and micrometeoroid bombardment in the space environment causes physical and chemical changes in the surface of an airless planetary body. These changes, called space weathering, can strongly influence a surface’s optical characteristics, and hence complicate interpretation of composition from reflectance spectroscopy. Prior work usi...
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We compared and assessed the results of measurements and observations by the Lunokhod 1 and Yutu rovers, both of which explored the northwestern part of Mare Imbrium. Both sites are within the distinctive Eratosthenian-aged lava flow geologic unit and our comparisons showed that the geologies of these exploration sites are very similar. As in the m...
Article
Quadrangle Av-10 ‘Oppia’ is one of five quadrangles that cover the equatorial region of asteroid (4) Vesta. This quadrangle is notable for the broad, spectrally distinct ejecta that extend south of the Oppia crater. These ejecta exhibit the steepest (‘reddest’) visible spectral slope observed across the asteroid and have distinct color properties a...
Article
In this work we present the spatial data analysis of the recently published global geologic and mineralogic maps of Vesta.
Article
We produced a geologic map of the Av-9 Numisia quadrangle of asteroid Vesta using Dawn spacecraft data to serve as a tool to understand the geologic relations of surface features in this region. These features include the plateau Vestalia Terra, a hill named Brumalia Tholus, and an unusual “dark ribbon” material crossing the majority of the map are...
Article
Full-text available
Abstract Oppia Quadrangle Av-10 (288–360°E, ±22°) is a junction of key geologic features that preserve a rough history of Asteroid (4) Vesta and serves as a case study of using geologic mapping to define a relative geologic timescale. Clear filter images, stereo-derived topography, slope maps, and multispectral color-ratio images from the Framing C...
Article
We used Dawn spacecraft data to identify and delineate geological units and landforms in the Marcia quadrangle of Vesta as a means to assess the role of the large, relatively young impact craters Marcia (~63. km diam.) and Calpurnia (~53. km diam.) and their surrounding ejecta field on the local geology. We also investigated a local topographic hig...
Article
We separated the respirable dust and other size fractions from Apollo 14 bulk sample 14003,96 in a dry nitrogen environment. While our toxicology team performed in vivo and in vitro experiments with the respirable fraction, we studied the size distribution and shape, chemistry, mineralogy, spectroscopy, iron content and magnetic resonance of variou...
Article
The two small asteroid-like bodies orbiting Mars, Phobos and Deimos, are low albedo and exhibit similar visible to near-infrared spectra. Determining the origin of these moons is closely tied to determining their composition. From available spectroscopic data Phobos exhibits two distinct types of materials across its surface, and data from both Mar...
Article
We report on a preliminary global geologic map of Vesta, based on data from the Dawn spacecraft's High-Altitude Mapping Orbit (HAMO) and informed by Low-Altitude Mapping Orbit (LAMO) data. This map is part of an iterative mapping effort; the geologic map has been refined with each improvement in resolution. Vesta has a heavily-cratered surface, wit...
Article
Anorthositic rocks dominate the Moon's upper crust. As remnants of the lunar magma ocean (LMO), small variations in the mineralogy of these rocks may hold key information about the homogeneity of LMO composition and solidification processes. Orbital near-infrared (NIR) sensors are sensitive to mineralogy, but technologic advances have only recently...
Article
NASA's Moon Mineralogy Mapper (M3) has identified and characterized a new lunar rock type termed pink spinel anorthosite (PSA) (Pieters et al., 2011). Dominated by anorthitic feldspar and rich in MgAl2O4 spinel, PSA appears to have an unusually low modal abundance of mafic silicates, distinguishing it from known lunar spinel-bearing samples. The in...
Article
Full-text available
Remote sensing observations have identified aluminate spinel, in the absence of measureable olivine and pyroxene, as a globally distributed component of the lunar crust. Earlier remote sensing observations and returned samples did not indicate the presence of this component, leaving its geologic significance unclear. Here, we report visible to mid-...
Article
Vesta spectra have prominent near-infrared absorption bands characteristic of pyroxenes, indicating a direct link to the howardite, eucrite and diogenite meteorites. Many localized dark and bright materials are present on Vesta’s surface. Here we focus on the bright material (BM) units to determine their spectral properties, their origin, the prese...