¹Lingzhi Sun,¹Paul G. Lucey,¹Abigail Flom,¹Chiara Ferrari-Wong,²Ryan A. Zeigler,^2,3Juliane Gross,⁴Noah E. Petro,⁵Charles K. Shearer,²Francis M. McCubbin,^VariousThe ANGSA Science Team
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13715]
¹Department of Earth Sciences, Hawai‘i Institute of Geophysics and Planetology, University of Hawai‘i at Manoa, 1680 East-West Rd, Honolulu, Hawai‘i, 96822 USA
²Astromaterials Acquisition and Curation Office, NASA Johnson Space Center, Houston, Texas, 77058 USA
³Department of Earth & Planetary Sciences, Rutgers State University of New Jersey, Piscataway, New Jersey, 08854 USA
⁴Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland, 20771 USA
⁵Institute of Meteoritics, Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico, 87131 USA
Published by arrangement with John Wiley & Sons

We measured the multispectral images and a hyperspectral profile during the first dissection pass of core 73002, and here, we present preliminary results. Both multispectral images and hyperspectral data show systematic darkening and reddening from bottom to top of the core, indicating an increasing maturity from the subsurface to surface soils. Our estimated FeO and TiO2 abundances are 9 (±1) wt% and 1.8 (±0.5) wt%, and their homogeneous distributions imply no compositional stratigraphy was sampled by core 73002. The in situ regolith reworking depth is about 14 cm as inferred from the optical maturity (OMAT) profile, corresponding to a time range of about 61 million years. Mineralogy and Mg# (molar Mg/[Mg+Fe]) calculated using hyperspectral data and radiative transfer modeling show as expected the core is dominated by plagioclase and low-Ca pyroxene, and the average Mg# is 61 (±10). Our work shows that spectroscopy has a great potential to be applied in the preliminary examination of future extraterrestrial samples from outside of the glovebox.

¹Yves Marrocchi,²Marco Delbo,³Matthieu Gounelle
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13716]
¹Université de Lorraine, CNRS, Centre de Recherches Pétrographiques et Géochimiques (CRPG), UMR 7358, Vandoeuvre␣les␣Nancy, F-54501 France
²Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Université Côte d’Azur, CS 34229, 06304 Nice, France
³IMPMC, Muséum national d’Histoire naturelle, CNRS, Sorbonne Universités, UMR 7590, 57 rue Cuvier, 75005 Paris, France
Published by arrangement with John Wiley & Sons

Chondrites are leftover solids from the early evolution of the solar protoplanetary disk that never experienced melting since their formation. They comprise unequilibrated assemblages of low- and high-temperature components, including volatile-rich, fine-grained matrices, Fe-Ni metal, sulfides, refractory inclusions, and chondrules. Consequently, chondrites are commonly described as pristine, primitive, or primordial rocks of the solar system. However, impact-generated secondary features are abundant in chondrites, suggesting that collisions among early-formed planetesimals and their fragmentation and reassembly have been effective throughout the evolution of the solar system. In this report, we review evidence of the major role of impacts in generating the current mineralogical and petrographic characteristics of chondrites. We provide perspective to these meteoritic features by discussing recent analyses of large-scale structures of the main asteroid belt and remote-sensing observations of asteroids. Observations at various spatial scales all attest that the “primitive” materials formed during the evolution of the solar system have largely been reprocessed, confirming previous studies that primitivity is relative, not absolute. This implies that (1) chondrites (and some differentiated meteorites) should systematically be envisioned as reprocessed and heterogeneous materials and (2) brecciated meteorites should be considered the norm and unbrecciated meteorites the exception.

¹Anicia Arredondo,¹Humberto Campins,²Noemi Pinilla-Alonso,^3,4Juliade León,³Vania Lorenzie,^5,6David Morat,^3,4Juan Luis Rizos,²Mário De Prá
Icarus (in Press) Link to Journal [https://doi.org/10.1016/j.icarus.2021.114619]
¹Physics Department, University of Central Florida, P.O. Box 162385, Orlando, FL 32816, USA
²Florida Space Institute, University of Central Florida, Orlando, FL 32816, USA
³Instituto de Astrofísica de Canarias, Tenerife, Spain
⁴Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain
⁵Fundación Galileo Galilei – INAF, La Palma, Tenerife, Spain
⁶Observatório Nacional, Coordenação de Astronomia e Astrofísica, 20921-400 Rio de Janeiro, Brazil
Copyright Elsevier

We present new near-infrared spectra of 55 objects observed using the NASA InfraRed Telescope Facility and the Telescopio Nazionale Galileo, along with visible spectra of 21 objects obtained from the SMASS and S3OS2 surveys, to explore the differences in spectral slope and curvature between the background and the families and to show that the background is a possible source for both Bennu and Ryugu. Within the background population there is spectral diversity in taxonomy, spectral slope, and absorption band parameters. Our sample of asteroids shows that the background looks spectrally similar to the families in the same region, i.e., the background and families may have originated from the same or similar composition parent bodies. Average band center (0.69 ± 0.02 μm, depth: 2.3 ± 0.9%) of an ~0.7 μm absorption feature attributed to aqueous alteration is present in 30% of our primitive background asteroid sample, similar to abundances observed in other primitive inner belt asteroid families. Both near-Earth asteroid sample return mission targets, (101955) Bennu and (162173) Ryugu, are thought to have originated from primitive asteroid populations in the inner main belt, specifically from the low inclination asteroid families. A population that has not been explored spectrally but is dynamically able to deliver asteroid fragments to near-Earth space is the background population, i.e., asteroids that do not cluster into families. Based on our spectral comparisons, the primordial background is a possible source for (162173) Ryugu, but not for (101955) Bennu.