Showing papers by "Smail Mostefaoui published in 2022"
TL;DR: In this paper , a nanoSIMS-based search for presolar material in samples recently returned from C-type asteroid Ryugu as part of JAXA's Hayabusa2 mission was conducted.
Abstract: We have conducted a NanoSIMS-based search for presolar material in samples recently returned from C-type asteroid Ryugu as part of JAXA's Hayabusa2 mission. We report the detection of all major presolar grain types with O- and C-anomalous isotopic compositions typically identified in carbonaceous chondrite meteorites: 1 silicate, 1 oxide, 1 O-anomalous supernova grain of ambiguous phase, 38 SiC, and 16 carbonaceous grains. At least two of the carbonaceous grains are presolar graphites, whereas several grains with moderate C isotopic anomalies are probably organics. The presolar silicate was located in a clast with a less altered lithology than the typical extensively aqueously altered Ryugu matrix. The matrix-normalized presolar grain abundances in Ryugu are 4.8−2.6+4.7 ppm for O-anomalous grains, 25−5+6 ppm for SiC grains, and 11−3+5 ppm for carbonaceous grains. Ryugu is isotopically and petrologically similar to carbonaceous Ivuna-type (CI) chondrites. To compare the in situ presolar grain abundances of Ryugu with CI chondrites, we also mapped Ivuna and Orgueil samples and found a total of 15 SiC grains and 6 carbonaceous grains. No O-anomalous grains were detected. The matrix-normalized presolar grain abundances in the CI chondrites are similar to those in Ryugu: 23−6+7 ppm SiC and 9.0−3.6+5.4 ppm carbonaceous grains. Thus, our results provide further evidence in support of the Ryugu–CI connection. They also reveal intriguing hints of small-scale heterogeneities in the Ryugu samples, such as locally distinct degrees of alteration that allowed the preservation of delicate presolar material.
7 citations
24 Feb 2022
TL;DR: In this paper , the dynamics of collisional events have been studied for three highly shocked L chondrites (Tenham, Sixiangkou, and Acfer 040).
Abstract: The dynamics of collisional events have been studied for three highly shocked L chondrites (Tenham, Sixiangkou, and Acfer 040). Crystal growth rates of high‐pressure polymorphs of olivines and pyroxenes and diffusion‐driven redistribution of Mn, Ca, Fe, and Na associated with these polymorphic transitions were studied independently. These two approaches were then applied on the same samples, and for meteorites that underwent different collisional histories. The relevance of the use of pyroxene polymorphs (e.g., akimotoite) is demonstrated. Combined analysis of the exact same ringwoodite and akimotoite crystals by scanning transmission electron microscopy (STEM) and NanoSIMS demonstrate that while STEM has a better lateral resolution, the 40 nm maximum resolution of the NanoSIMS is sufficient to distinguish and analyze diffusion profiles. With STEM chemical and structural information concerning the nucleation mechanisms of ringwoodite and akimotoite, the concentration profiles derived from NanoSIMS images were used to derive the shock pulse duration and impactor size for these three meteorites. The two approaches (crystal growth kinetics and elemental diffusion) provide comparable durations assuming that diffusion coefficients are carefully selected. We obtain shock time scales of 1, 7, and 4 s for Tenham, Sixiangkou, and Acfer 040, respectively. Corresponding impactor sizes are also calculated, and the results point toward either (i) an early separation of the L chondrites from the parent body, and secondary impacts resulting in the observed meteorites or (ii) the meteorites all originate from different depths in the parent body.
1 citations
TL;DR: In this article , Rojas et al. present a nanosims study of the carbinear antagonism in the context of space magnetic resonance imaging (SVM).
Abstract: CARBONACEOUS ANTARCTIC MICROMETEORITES: A NANOSIMS STUDY. J. Rojas, J. Duprat, L. R. Nittler, E. Dartois, C. Engrand, N. Bardin, B. Guerin, L. Delauche, S. Mostefaoui, L. Rémusat, R. M. Stroud, T-D Wu. Univ. Paris-Saclay, CNRS, IJCLab, 91405 Orsay, France (Julien.Rojas@ijclab.in2p3.fr); IMPMC, CNRS, MNHN, Sorbonne Univ., 75005 Paris, France Earth and Planets Laboratory, Carnegie Institution of Washington, Washington, DC 20015, USA, Univ. Paris-Saclay, CNRS, ISMO, 91405 Orsay, France, Naval Research Laboratory, Washington, DC 20375, USA, Institut Curie, PSL Research Univ., INSERM, U1196, 91405 Orsay, France.
1 citations
01 Jan 2022
TL;DR: Remusat, B. Doisneau, S. Mostefaoui, O.Beyssac, H.Leroux, and M. Gounelle as mentioned in this paper .
Abstract: Remusat, B. Doisneau, S. Mostefaoui, O.Beyssac, H.Leroux, and M. Gounelle. IMPMC, CNRS, UMR 7590, Sorbonne Université, Muséum National d'Histoire Naturelle, CP 52, 57 rue Cuvier, Paris F-75231, France Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), 4 Place Jussieu, 75005 Paris, France 3 Univ. Lille, CNRS, INRAE, Centrale Lille, UMR 8207 UMET Unité Matériaux et Transformations, F-59000 Lille, France
TL;DR: In this paper , the authors proposed an approach to solve the problem of energy minimization in the context of light-emitting diodes (LiDAR) and showed that it is possible to achieve energy minimisation in the presence of a large amount of energy.
Abstract: Engrand3, Y. Kebukawa4, B. De Gregorio5, L. Bonal6, L. Remusat7, R. Stroud5, E. Quirico6, L. R. Nittler2, M. Hashiguchi8, M. Komatsu9, E. Dartois10, J. Mathurin11, J. Duprat7, T. Okumura12, Y. Takahashi12, Y. Takeichi13, D. Kilcoyne14, S. Yamashita13, A. Dazzi11, A. Deniset-Besseau11, S. Sandford15, Z. Martins16, Y. Tamenori17, T. Ohigashi18, H. Suga17, D. Wakabayashi13, M. Verdier-Paoletti7, S. Mostefaoui7, G. Montagnac19, J. Barosch2, K. Kamide1, M. Shigenaka1, L. Bejach3, T. Noguchi20, H. Yurimoto21, T. Nakamura22, R. Okazaki23, H. Naraoka23, K. Sakamoto24, S. Tachibana12,24, S. Watanabe8, and Y. Tsuda24, 1Hiroshima Univ., 1-3-1 Kagamiyama, HigashiHiroshima, Hiroshima 739-8526, Japan. 2Carnegie Institution of Washington, USA. 3IJCLab, Univ. ParisSaclay/CNRS, France. 4Yokohama National Univ., Japan. 5U.S. Naval Research Laboratory, USA, 6Université Grenoble Alpes, France. 7Muséum national d'Histoire naturelle, France. 8Nagoya Univ., Japan. 9The Graduate Univ. for Advanced Studies (Sokendai), Japan. 10ISMO, Univ. Paris-Saclay/CNRS, France. 11ICP, Univ. Paris-Saclay/CNRS, France. 12Univ. of Tokyo, Japan, 13High Energy Accelerator Research Organization, Japan. 14Advanced Light Source, USA. 15NASA Ames Research Center, USA. 16Instituto Superior Técnico, Portugal. 17SPring8, Japan. 18UVSOR, IMS, Japan. 19ENS Lyon, France, 20Kyoto Univ., Japan. 21Hokkaido Univ., Japan. 22Tohoku Univ., Japan. 23Kyushu Univ., Japan. 24ISAS, JAXA Japan.
TL;DR: Rojas et al. as discussed by the authors proposed a method to detect Heterogeneous Ices using a multimodal imaging (IMPMC) system, which can be found in the image of the human body.
Abstract: topically Heterogeneous Ices. J. Rojas, J. Duprat, E. Dartois, T-D. Wu, C. Engrand, L. R. Nittler, N. Bardin, B. Augé, Ph. Boduch, H. Rothard, M. Chabot, L. Delauche, S. Mostefaoui, L. Rémusat, R. M. Stroud, B. Guérin; Univ. Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France (Julien.Rojas@ijclab.in2p3.fr), 2 IMPMC, CNRS-MNHN-Sorbonne Univ., 75005 Paris, France, 3 Univ. Paris-Saclay, CNRS, ISMO, 91405 Orsay, France, 4 Institut Curie, PSL Univ., Univ. Paris-Saclay, CNRS UMS2016, Inserm US43, Multimodal Imaging Center, 91405 Orsay, France, Earth and Planets Laboratory, Carnegie Institution of Washington, Washington, DC 20015, USA, IPAG, Univ. Grenoble Alpes, CNRS, 38000 Grenoble, France, CIMAP, 14070 Caen, France, Naval Research Laboratory, Washington, DC 20375, USA