^1,2,3Zélia Dionnet et al. (>10)
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.13807]
¹Institut d’Astrophysique Spatiale, CNRS, Université Paris-Saclay, Orsay, 91405 France
²Dip. Di Scienze Applicate, Università di Napoli Parthenope, Centro Direzionale di Napoli, Isola C4, Naples, 80143 Italy
³Istituto di Astrofisica e Planetologia Spaziali—INAF, Rome, Italy
Published by arrangement with John Wiley & Sons

In this paper, we report the results of a campaign of measurements on four fragments of the CM Aguas Zarcas (AZ) meteorite, combining X-ray computed tomography analysis and Fourier-transform infrared (FT-IR) spectroscopy. We estimated a petrologic type for our sampled CM lithology using the two independent techniques, and obtained a type CM2.5, in agreement with previous estimations. By comparing the Si-O 10-µm signature of the AZ average FT-IR spectra with other well-studied CMs, we place AZ in the context of aqueous alteration of CM parent bodies. Morphological characterization reveals that AZ has heterogeneous distribution of pores and a global porosity of 4.5 ± 0.5 vol%. We show that chondrules have a porosity of 6.3 ± 1 vol%. This larger porosity could be inherited due to various processes such as temperature variation during the chondrule formation and shocks or dissolution during aqueous alteration. Finally, we observed a correlation between 3D distributions of organic matter and mineral at micrometric scales, revealing a link between the abundance of organic matter and the presence of hydrated minerals. This supports the idea that aqueous alteration in AZ’s parent body played a major role in the evolution of the organic matter.

¹C.M.Lisse,^2.3J.K.Steckloff
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2022.114995]
¹Space Exploration Sector, Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD, USA 20723
²Planetary Science Institute, Tucson, AZ 85719, USA
³Department of Aerospace Engineering and Engineering Mechanics, University of Texas at Austin, Austin, TX 78712, USA
Copyright Elsevier

In 2010 Jewitt and Li published a paper examining the behavior of “comet-asteroid transition object” 3200 Phaethon, arguing it was asteroid-like in its behavior throughout most of its orbit, but that near its perihelion, at a distance of only 0.165 AU from the sun, its dayside temperatures would be hot enough to vaporize rock (>1000 K, Hanus et al., 2016). Thus it would act like a “rock comet” as gases produced from evaporating rock were released from the body, in a manner similar to the more familiar sublimation of water ice into vacuum seen for comets coming within ~3 AU of the Sun. In this Note we predict that the same thermal effects that would create “rock comet” behavior with Qgas ~ 1022 mol/s at perihelion would also help bluen the surface via preferential thermal alteration and sublimative removal of surface Fe and refractory organics, known reddening and darkening agents. These predictions are testable by surveying other objects on Phaethon-like small perihelion orbits, and by in situ measurements from the upcoming DESTINY+ mission to Phaethon by JAXA.