The Reflectance Spectra of CV-CK Carbonaceous chondrites from the Near Infrared to the Visible

By Keith Cowing
July 28, 2021
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The Reflectance Spectra of CV-CK Carbonaceous chondrites from the Near Infrared to the Visible
Back-scattered electron (BSE) image of regions of CK4 chondrite ALH 85002. It is a nice example of well preserved CK consisting of well compacted silicate-rich chondrules, sulfides and accessory minerals. The dominant minerals and their respective tonality are: olivine – light gray; orthopyroxene – medium gray; plagioclase – dark gray; sulfide and magnetite – white; fractures and pores being black.

Carbonaceous chondrite meteorites are so far the only available samples representing carbon-rich asteroids and in order to allow future comparison with samples returned by missions such as Hayabusa 2 and OSIRIS-Rex, is important to understand their physical properties.

Future characterization of asteroid primitive classes, some of them targeted by sample-return missions, requires a better understanding of their mineralogy, the consequences of the exposure to space weathering, and how both affect the reflectance behavior of these objects. In this paper, the reflectance spectra of two chemically-related carbonaceous chondrites groups, precisely the Vigrano (CVs) and Karoonda (CKs), are measured and compared. The available sample suite includes polished sections exhibiting different petrologic types: from 3 (very low degree of thermal metamorphism) to 5 (high degree of thermal metamorphism). We found that the reflective properties and the comparison with the Cg asteroid reflectance class point toward a common chondritic reservoir from which the CV-CK asteroids collisionally evolved.

In that scenario the CV and CK chondrites could be originated from 221 Eos asteroid family, but because of its collisional disruption, both chondrite groups evolved separately, experiencing different stages of thermal metamorphism, annealing and space weathering.

Safoura Tanbakouei, J.M.Ttigo-Rodriquez, J.Llorca, C.E.Moyano-Cambero, I.P.Williams, A.S. Rivkin

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2107.12590 [astro-ph.EP] (or arXiv:2107.12590v1 [astro-ph.EP] for this version)
Submission history
From: Safoura Tanbakouei
[v1] Tue, 27 Jul 2021 04:21:21 UTC (4,620 KB)


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