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NASA NTRSDate not supplied

Understanding Olivine and Pyroxene in Chondritic IDPs

There is a widespread depletion of Cr from the FeO-rich olivine in Wild-2, relative to type IIA chondrules(Frank et al., 2014)-the degree of this depletion is akin to that in unequilibrated chondrites such as Krymka (LL3.2) or Rainbow (CO3.2).Since Cr is highly mobile under even mild thermal metamorphism(as low as 200ºC), it is a sensitive indicator of such an event, showing greater depletion in smaller grains (i.e., matrix vs. chondrules) (Grossman and Brearley, 2005). Grossman and Brearley (2005) found that the distribution of Cr in FeO-rich olivine systematically changes as metamorphism increases between type 3.0 and type 3.2. Thus, Wild-2 olivine appears to carry evidence of mild thermal metamorphism. It is critical to determine whether there is any evidence for this from samples of other comets. For this we can examine an hydrous chondritic IDPs. Unfortunately, the data for olivine and pyroxene in IDPs is sparse, mainly decades old and lacks useful information on minor elements. We have begun to collect new compositional data for olivine and pyroxene in chondritic interplanetary dust particles (filling a major gap in our knowledge, as approximately half of these grains derive from comets), to determine whether the results obtained for Wild-2 are typical for comets in general, or whether Wild-2 (or its accretion components) has experienced an atypical geological history. A determination that a comet, or its accretion components, had experienced significant thermal metamorphism would greatly alter models of early solar system history.

Michael Zolensky↗

NASA NTRSDate not supplied

Petrologic Sub-types, Sub-groups, and Pairing for CV Chondrites in the US Antarctic Meteorite Collection

Carbonaceous chondrites of the Vigarano group (CV) are primitive meteorites that provide a wealth of information about the early solar system, including constraints on chondrule formation, origin of calcium-aluminum inclusions, stability of organic compounds, and redox conditions. The US Antarctic meteorite collection contains 119 CV samples from 15 dense collection areas (DCAs) from the Trans-Antarctic Mountains. These samples have been assigned a preliminary classification as CVs, but have not been assigned to the subgroups Oxidized A, Oxidized B, and Reduced. Additionally, variation in petrologic grade can be determined non-destructively using Raman spectroscopy. In order to update classification of both subgroups and petrologic types in the collection, we have acquired magnetic susceptibility, metal and sulfide compositions, and Raman spectra, for as many samples as possible. We use the recent assessment and delineation of CV sub-groups of as a guide.

solar nebula↗

NASA NTRSDate not supplied

A Record of Nebular and Parent Body Processes of Grossite-Bearing, Fine-Grained Refractory Inclusions from Reduced CV3 Chondrites

Grossite (CaAl4O7) is predicted to condense as the third major phase, after corundum and hibonite, from a cooling gas of solar composition and likely preserves an important record of physico-chemical conditions in the early Solar System. However, this mineral is relatively rare in CAIs from most carbonaceous chondrite groups, except for CH chondrites. In particular, from CV3 chondrites where CAIs are large and abundant, only six grossitebearing CAIs have been reported and studied, and most of them were coarse-grained Type A inclusions. Here, we report the occurrence of grossite-bearing, fine-grained inclusions (FGIs) from reduced CV3 chondrites. We present preliminary results of a FIB/TEM study of one grossite-bearing FGI that provide clues to constrain its formation and alteration history in the solar nebula and on the parent body and to address the overall rarity of grossite in CAIs.

J. Han↗

NASA NTRSDate not supplied

Requesting Antarctic Meteorite Samples for Research

The U.S. Antarctic meteorite program began in the 1970’s and has provided more than 24,000 samples. The program is based on a three agency agreement between NASA, the National Science Foundation, and the Smithsonian Institution. The collection, stored at the Johnson Space Center and the Smithsonian, is one of the largest collections of meteorites in the world and features samples from the moon, Mars, asteroids, and material from the early solar system. A brief overview of the collection shows it contains 92.2% ordinary chondrites (7205 H, 9126 L, 3890 LL, 146 enstatite, 30 R chondrites, 3.2% (973) carbonaceous chondrites, 3.7% (560) achondrites (1.7% HED), 118 irons, 27 pallasites, 41 mesosiderites, as well as many puzzling, ungrouped meteorites. JSC has sent splits of over 20,000 meteorite samples to more than 500 scientists around the world since 1977. After the meteorites are collected in Antarctica, they are shipped frozen to JSC in Houston, TX, arriving in April following the field season. The Astromaterials Curation Office at JSC is responsible for: - providing supplies and tools for the field team. - receiving the frozen meteorites. - staging: repackaging and changing the samples’ field identification numbers with official names. - submitting the names to the Nomenclature Committee of the Meteoritical Society for approval as new meteorites. - providing storage and handling of the meteorites in a class 10,000 clean room. - initial processing: weighing, measuring, describing, and photographing the sample and providing a chip for classification to the Smithsonian Institution staff. - the issuing of two newsletters per year, announcing hundreds of new meteorites. - the handling of requests from the scientific community and the allocation of those requests that are approved. - making petrographic thin and thick sections for the JSC library and scientific investigators. - maintaining the meteorite database with more than 76,000 sample splits.

C.E. Satterwhite↗

NASA NTRS2022

Mapping Phyllosilicates on the Asteroid Bennu Using Thermal Emission Spectra and Machine Learning Model Applications

Bennu, the target of the OSIRIS-REx mission, is an asteroid with compositions analogous to low petrologic type CI, CM, CR, and/or ungrouped carbonaceous chondrites. Asteroids like Bennu provide information about the building blocks of the early Solar System. Analysis of the mid-infrared remote sensing data informs mineral quantification. We apply a phyllosilicate specific model, developed by Breitenfeld et al. (2021) that distinguishes between Mg and Fe serpentines, to Baseball Diamond 1 (BBD1), Equatorial Station 3 (EQ3), and Touch-And-Go OSIRIS-REx Thermal Emission Spectrometer data. The average total phyllosilicate predictions are 73 (BBD1) and 72 vol% (EQ3). We observe higher Fe-cronstedtite and lower Mg-rich serpentine content in the equatorial region of Bennu than average. Mid-infrared spectral variability may be explained by sorting effects through mass movement.

Bennu↗

NASA NTRSDate not supplied

Technology Gaps for Rapid Response Missions to Near-Earth Objects, Interstellar Objects, and Long-Period Comets

The last several years has seen the discovery of the first two interstellar objects, the first ever planetary defense mission, recommendation for a rapid reconnaissance planetary defense demonstration, and the continued emergence of a robust commercial small satellite industry. The present and near future also consist of emerging next-generation observatories including Vera Rubin and NEO Surveyor. These seemingly disparate events converge in the context of rapid response: a cross-cutting capability that would enable NASA and the international community to quickly discover and respond to an emerging target such as a near-Earth object (NEO), interstellar object (ISO), or long-period comet (LPC) either for rapid characterization of a potential threat, or revolutionary science that would inform early solar system formation and evolution. In late October 2022, subject matter experts gathered at the California Institute of Technology in a week-long workshop sponsored by the Keck Institute for Space Studies (KISS) to address enabling mission concepts for rapid response and key technology gaps (final report in progress). These experts concurred that the ability to respond on the order of a few months is necessary for rapid in-situ characterization of a NEO, ISO, or LPC, and that while there are several technology gaps, this capability could be realized in the near future.

Technology gaps↗

NASA NTRS2023

Direct Analyses of Aqueous Fluids from C-Class Asteroid 162173 Ryugu

Imaging using X-ray absorption contrast by synchrotron nano-computed tomography (47.4 nm/voxel, 7keV) of a Ryugu pyrrhotite crystal revealed probable fluid inclusions. The inclusions were completely encapsuled in pyrrhotite, suggesting the fluids were trapped in the early stages of crystal growth, and filled with low-Z material. We performed Time-of Flight-Secondary Ion Mass Spectrometry (TOF-SIMS) depth profiling and high-resolution mapping at -120°C to exposure and measure the composition of the trapped fluids in a frozen state. These measurements revealed that the ancient, trapped fluids on Ryugu’s parent asteroid were saline aqueous solutions containing H2O, CO2, sulfur species, and nitrogen- and chlorine-bearing organic compounds identified by representative secondary ion species including O(-), OH(-), CO(-), S(-), Cl(-), C2(-), C2H(-), and CN(-). The inferred presence of CO2 indicates formation of the sulfides, and by implication the Ryugu parent body, beyond the H2O and CO2 snow lines of the early solar system, i.e. > 3-4 au from the Sun.

M Zolensky↗

NASA NTRSDate not supplied

A Chlorine Isotope Transect Across the Sudbury Impact Deposits Reveals Enigmatic Isotopic Fractionation

Volatile elements play an important role in a variety of cosmochemical and geochemical processes. As such, there has been significant interest in their abundance and isotopic composition. Chlorine is an important element for tracing these processes because it is incompatible in nearly all minerals, extremely volatile, and strongly hydrophilic [1]. The Cl isotope composition ( 37 Cl/ 35 Cl) of meteoritic components, therefore, can provide useful information regarding the isotopic reservoirs that were present in the early Solar System and any secondary processes that may have occurred on different parent bodies (e.g., [2-4]). There is a relatively narrow range in the Cl isotope compositions of terrestrial, Martian, and chondritic meteorites (δ 37 Cl ~ −6 to +4‰) (e.g., [2,3,5,6]), with exceptions to this being the Moon and Vesta (up to ~ +81‰ and ~ +40‰, respectively) [4, 5, 7-10]. One hypothesis for the extreme Cl isotope fractionation observed on the Moon is degassing following large-scale (possibly even crust-breaching) impact events [7-9]. The role of hypervelocity impacts and impact-generated magmatism in the isotopic evolution of planetary materials, however, has been until recently an area of limited published research with the majority of works focusing on the effects of impact shock (e.g., [10-13]). The ~ 1.85 Ga Sudbury impact crater [14] located in Ontario, Canada, is one of the three largest impact craters on Earth with good exposures of its impact melt sheet and overlying breccias [15,16]. The impact melt sheet, called the Sudbury Igneous Complex (SIC), is up to 5 km thick [17], with an estimated original volume of >10 4 km 3 [18], and differentiated. Recent work demonstrated evaporative loss and isotope fractionation of the moderately volatile element zinc and suggest melt sheets produced by impacts could have a significant effect on the Earth’s volatile inventory [19]. In this study we investigate the abundance and isotopic composition of Cl as well the water abundance of apatite from the SIC and the overlying crater-fill to test the hypothesis that large-scale impacts may have generated the extensive Cl isotopic fractionation observed on the Moon.

Sudbury↗

NASA NTRSDate not supplied

The Chemical and Isotopic Signatures of the Hibonite-rich FUN Inclusion "HIDALGO" in Dar al Gani 027 (CO3)

Refractory Ca-Al-rich Inclusions (CAIs) with FUN (Fractionation with Unidentified Nuclear effects) characteristics are peculiar samples among all high-temperature components in chondritic meteorites. They are generally characterized by strong mass-dependent isotopic fractionations in several elements (e.g., O, Mg, Ca, Ti), large (~5-20‰) enrichments or depletions in neutron-rich isotopes (e.g., 48 Ca, 50 Ti, 54 Cr), and low inferred abundances of 26 Al ( 26 Al/ 27 Al < 1×10 −5 ). Understanding the origins of these features in FUN CAIs can shed light on the astrophysical environment and chemical processes that took place in the early Solar System. A large fraction (slightly less than 50%) of the ~20 FUN CAIs discovered so far are hibonite-rich (such as HAL, SHAL and DH-H1, collectively called HAL-type inclusions hereafter). According to their elemental and isotopic signatures and the results of evaporation experiments, HAL-type inclusions are thought to have formed as a distillation residue. However, questions regarding the timing of the formation of HAL-type inclusions (or FUN inclusions in general) relative to those of regular CAIs and the decoupling between the 26 Al abundances and nucleosynthetic anomalies remain poorly understood. In 2021, we reported the discovery of a new HAL-type inclusion, HIDALGO (Hibonite in Dar al Gani CO3) in the CO3 chondrite Dar al Gani 027 (DaG027), based on its (fractionated) oxygen isotopic compositions and low inferred 26 Al/ 27 Al ratio of (1.50±0.02)×10 −5 . Since then, more work on other short-lived and stable isotope systems and trace element abundances has been conducted. Here we report these new results and discuss the implications for the possible formation history of HIDALGO and origins of shortlived radionuclides (SLRs).

Meteorite↗

NASA NTRS2018

Fe-Ni Mobilization in Primitive Co Chondrites: Implications for Progressive Aqueous Alteration in the Parent Body

Chondrites that escaped significant secondary alteration are essential for investigating isotopic signatures of the protosolar nebula and constraining early solar system chronology. Telus et al. showed that fluid-induced Fe and Ni mobilization occurred even in the most unequilibrated ordinary chondrites (UOCs), both falls and finds. CO3.0s are more pristine than ordinary chondrites of the same petrologic type, based on presolar silicate grain abundances [2]. Here, we extend the study of [1] by analyzing the Fe and Ni distributions in CO3.0s, ALHA 77307, DOM 08006, DOM 10104, and MIL 090038, and Acfer 094 (ungrouped C3.0) to better characterize the alteration history of these primitive chondrites. We are especially interested in whether these chondrites are good candidates for studying the Fe-60-Ni-60 systematics of chondrules.

M Telus↗

NASA NTRS2023

Soluble Organic Molecules in Samples of the Carbonaceous Asteroid (162173) Ryugu

The Hayabusa2 spacecraft collected samples from the surface of the carbonaceous near-Earth asteroid (162173) Ryugu, and brought them to Earth. The samples were expected to contain organic molecules, which record processes that occurred in the early Solar System. We analyzed organic molecules extracted from the Ryugu surface samples. We identify a variety of molecules containing the atoms CHNOS, formed by methylation, hydration, hydroxylation, and sulfurization reactions. Amino acids, aliphatic amines, carboxylic acids, polycyclic aromatic hydrocarbons, and nitrogen-heterocyclic compounds were detected, with properties consistent with an abiotic origin. These compounds likely arose from aqueous reaction on Ryugu’s parent body and are similar to organics in Ivuna-type meteorites. These molecules can survive on the surfaces of asteroids and be transported throughout the Solar System.

Hiroshi Naraoka↗

NASA NTRS2023

The Magnesium Isotope Composition of Samples Returned From Asteroid Ryugu

The nucleosynthetic isotope composition of planetary materials provides a record of the heterogeneous distribution of stardust within the early solar system. In 2020 December, the Japan Aerospace Exploration Agency Hayabusa2 spacecraft returned to Earth the first samples of a primitive asteroid, namely, the Cb-type asteroid Ryugu. This provides a unique opportunity to explore the kinship between primitive asteroids and carbonaceous chondrites. We report high-precision μ 26 Mg* and μ 25 Mg values of Ryugu samples together with those of CI, CM, CV, and ungrouped carbonaceous chondrites. The stable Mg isotope composition of Ryugu aliquots defines μ 25 Mg values ranging from –160 ± 20 ppm to –272 ± 30 ppm, which extends to lighter compositions relative to Ivuna-type (CI) and other carbonaceous chondrite groups. We interpret the μ 25 Mg variability as reflecting heterogeneous sampling of a carbonate phase hosting isotopically light Mg (μ 25 Mg ∼ –1400 ppm) formed by low temperature equilibrium processes. After correcting for this effect, Ryugu samples return homogeneous μ 26 Mg* values corresponding to a weighted mean of 7.1 ± 0.8 ppm. Thus, Ryugu defines a μ 26 Mg* excess relative to the CI and CR chondrite reservoirs corresponding to 3.8 ± 1.1 and 11.9 ± 0.8 ppm, respectively. These variations cannot be accounted for by in situ decay of 26 Al given their respective 27 Al/ 24 Mg ratios. Instead, it requires that Ryugu and the CI and CR parent bodies formed from material with a different initial 26 Al/ 27 Al ratio or that they are sourced from material with distinct Mg isotope compositions. Thus, our new Mg isotope data challenge the notion that Ryugu and CI chondrites share a common nucleosynthetic heritage.

Solar system evolution↗

NASA NTRS2024

Constraining the Thermal and Textural Evolution of Evolved Achondrite DOM 10100: Implications for Volatile Loss

Identification of evolved achrondritic clasts suggests that some early planetesimals experienced extensive differentiation and formed chemically evolved crusts. Many of these samples contain volatile-bearing phases (i.e., apatite, merrillite, nominally anhydrous minerals), which can be used to constrain volatile budgets and abundancies via in-situ measurements. These ancient crustal rocks are subject to high heat, moderate pressures, potentially hot mineral-rich fluids, and degassing that has likely modified many of these volatiles, and their abundancies do not represent the composition of the primary magma from which these achondrites formed. In this work we attempt to deconvolve the thermal evolution of these samples to provide petrologic information that can be used for making inferences regarding their volatile history, and ultimately constraining volatile budgets on planetary bodies in the early Solar System. Here, we combine in-situ major element geochemistry, thermodynamic modeling, and detailed textural and microstructural observations to reconstruct the thermal and textural evolution of howardite DOM 10100, which contains a dacite within its matrix. Previous analyses of several sections of DOM 10100 suggest that the dacitic clast is evidence for partial melting of Vesta’s differentiated basaltic crust, making it an ideal candidate for evolved crustal studies. While its igneous petrogenesis has been well constrained, there is still opportunity to better characterize its post-crystallization thermal history, including possible thermal metamorphism and cooling.

J S Gorce↗

NASA NTRS2024

Ubiquitous Presence of Sodium-Bearing Magnesium Phosphate in CI Chondritic Materials

The discovery that the asteroid Ryugu samples returned by the JAXA Hayabusa2 spacecraft are chemically and mineralogically nearly identical to CI chondrites has made us re-recognize the importance of CI chondrites in the early solar system [e.g., 1]. These CI chondritic materials have undergone strong aqueous alteration in their parent bodies, resulting in the formation of abundant Mg-Fe phyllosilicates along with other altered minerals such as carbonates, magnetite, and pyrrhotite. Initial and subsequent AO analyses of the Ryugu samples have found that they are brecciated on the mm~μm scale and that a small amount of forsterite and other primary minerals survive in some of the brecciated clasts with evidence of less degrees of aqueous alteration (“less altered clast”) [e.g., 1]. In addition, these less altered clasts contain a rare Na-bearing Mg phosphate that is still poorly characterized. Despite the analytical attempt to identify its mineral species, their identity has not been clarified yet. These rare Mg phosphates could be one of the key phases to understanding the evolution of CI chondritic bodies since a similar Na-bearing Mg phosphate has been reported from the asteroid Bennu sample returned by the NASA OSIRIS REx mission, and the importance of these materials has been suddenly highlighted. Since the initial analysis of the Ryugu sample, we have been paying attention to these Mg phosphates in CI chondrites as well as Ryugu samples, and here we report the present results on their mineralogical analysis.

T Mikouchi↗

NASA NTRSDate not supplied

Insights Into the CM Parent Body's Interior: A Comparative Study With Bennu's Bright Boulders

CM (Mighei-like) chondrites, primitive and water-rich asteroid samples from the early solar system, are significant for their potential role in delivering water and organic compounds to Earth [1-2]. Their resemblance to near-Earth asteroids Bennu and Ryugu, the targets of recent sample return missions, highlights their importance. What we learn from CM chondrites can be applied to these intriguing celestial bodies. Initial studies indicated that phyllosilicate-rich C chondrites underwent low-temperature aqueous alteration (<150°C) [3-5]. Subsequent research revealed that some experienced post-hydration thermal metamorphism at temperatures between ∼200°C and >750°C, resulting in dehydrated minerals and reduced volatile elements [6-9].This finding challenged the previous assumption that these chondrites had not undergone significant thermal metamorphism.

I Kerraouch↗

NASA NTRSDate not supplied

Trace Element and Isotopic Evidence for Bennu's Primitive Provenance

The delivery of material from asteroid (101955) Bennu by NASA’s OSIRIS-REx mission provides the opportunity to investigate some of the most pristine material from the early Solar System [1]. Our team at Lawrence LivermoreNational Laboratory (LLNL) utilized the equivalent of 5.0 mg from Bennu sampleOREX-803015-100 to quantify the major and trace element contents and investigate major element isotopics (Ca, Ti, Cr, Fe, and Ni). Our 5.0 mg aliquot ofOREX-803015-100 was a subsample of dissolved homogenized material representing 20.66 mg [2]. A separate 5.0 mg aliquot was sent to ETH Zürich and is discussed in a companion abstract [3]. Before any chemical separation on our 5.0 mg aliquot, the equivalent of 0.5 mg was removed and analyzed for elemental abundances at LLNL using a ThermoScientific Element XR. Our data agree exceptionally well with those reported by[2], showing that Bennu is primitive and compositionally similar to CI chondrites, Ryugu [4], and the solar photosphere [5]. The remaining ~4.5 mg underwent purification procedures to chemically isolate and purify Ca, Ti, Cr, Fe, and Ni from one another and the sample matrix. Their isotopic compositions were measured on either the Triton TIMS (Ca) at JohnsonSpace Center in Houston, Neoma MC-ICPMS (Ti, Cr) at LLNL, or the Neptune MC-ICPMS (Fe, Ni) at LLNL. Results from the Ca, Ti, Cr, Fe, and Ni isotopic compositions suggest that Bennu is closely related to CI chondrites—consistent with conclusions from elemental composition [2] and oxygen isotopics [6]reported for Bennu. The major element isotope compositions that we will present demonstrate that Bennu likely formed in a similar region of the SolarSystem as CI chondrites and potentially at a similar time of Solar System evolution.

Greg Brennecka↗

NASA NTRS2024

Analysis of Ryugu Fluid Inclusions: An Update

The most direct and convincing evidence for the presence of water and organic molecules on protoplanetary bodies is provided by fluid inclusions trapped in secondary minerals. Our previous work has demonstrated that early solar system fluids have survived as fluid inclusions in a Ryugu pyrrhotite crystal [2]. We hypothesize that the bulk molecular and isotopic composition of individual Ryugu fluid inclusions can be measured to provide ground truth for exploring and thermochemical modeling of the compositional and isotopic evolution of fluids in protoplanetary bodies including asteroids, comets and icy moons. This presentation is an update on our efforts to make measurements of elemental, molecular and, in particular, isotopic compositions of individual aqueous fluid inclusions in Ryugu samples. The measurements we plan will permit us to (1) understand elemental composition of the aqueous fluids present on Ryugu’s progenitor body, (2) track changes in the chemical and stable isotopic composition of altering fluids in small bodies over time, (3) verify the presence of organics in Ryugu fluids, (4) verify the reported significant CO 2 in Ryugu fluids, (5) measure O and H isotopes in preserved Ryugu fluids, (6) provide constraints on temperature range calculations for the mineralizing reactions being performed by other groups using mineral pairs, (7) measure sulfur/chloride and chloride/phosphorus ratios of Ryugu fluids. We note here that recent results from Enceladus reveal the importance of phosphorus in small body aqueous brines, indicating that our proposed research will benefit studies of all current ocean worlds.

Andrei Dolocan↗

NASA NTRS2025

Abundant Ammonia and Nitrogen-Rich Soluble Organic Matter in Samples From Asteroid (101955) Bennu

Organic matter in meteorites reveals clues about early Solar System chemistry and the origin of molecules important to life, but terrestrial exposure complicates interpretation. Samples returned from the B-type asteroid Bennu by the Origins, Spectral Interpretation, Resource Identifcation, and Security–Regolith Explorer mission enabled us to study pristine carbonaceous astromaterial without uncontrolled exposure to Earth’s biosphere. Here we show that Bennu samples are volatile rich, with more carbon, nitrogen and ammonia than samples from asteroid Ryugu and most meteorites. Nitrogen-15 isotopic enrichments indicate that ammonia and other N-containing soluble molecules formed in a cold molecular cloud or the outer protoplanetary disk. We detected amino acids (including 14 of the 20 used in terrestrial biology), amines, formaldehyde, carboxylic acids, polycyclic aromatic hydrocarbons and N-heterocycles (including all fve nucleobases found in DNA and RNA), along with ~10,000 N-bearing chemical species. All chiral non-protein amino acids were racemic or nearly so, implying that terrestrial life’s left-handed chirality may not be due to bias in prebiotic molecules delivered by impacts. The relative abundances of amino acids and other soluble organics suggest formation and alteration by low-temperature reactions, possibly in NH3-rich fuids. Bennu’s parent asteroid developed in or accreted ices from a reservoir in the outer Solar System where ammonia ice was stable.

Daniel P Glavin↗