Comparing the reflectivity of ungrouped carbonaceous chondrites with that of short period comets like 2P/Encke

Aims. The existence of asteroid complexes produced by the disruption of these comets suggests that evolved comets could also produce high-strength materials able to survive as meteorites. We chose as an example comet 2P/Encke, one of the largest object of the so-called Taurid complex. We compare the reflectance spectrum of this comet with the laboratory spectra of some Antarctic ungrouped carbonaceous chondrites to investigate whether some of these meteorites could be associated with evolved comets. Methods. We compared the spectral behaviour of 2P/Encke with laboratory spectra of carbonaceous chondrites. Different specimens of the common carbonaceous chondrite groups do not match the overall features and slope of the comet 2P/Encke. By testing anomalous carbonaceous chondrites, we found two meteorites: Meteorite Hills 01017 and Grosvenor Mountains 95551, which could be good proxies for the dark materials that formed this short-period comet. We hypothesise that these two meteorites could be rare surviving samples, either from the Taurid complex or another compositionally similar body. In any case, it is difficult to get rid of the effects of terrestrial weathering in these Antarctic finds, and further studies are needed. A future sample return from the so-called dormant comets could also be useful to establish a ground truth on the materials forming evolved short-period comets. Results. As a natural outcome, we think that identifying good proxies of 2P/Encke-forming materials might have interesting implications for future sample-return missions to evolved, potentially dormant, or extinct comets. Understanding the compositional nature of evolved comets is particularly relevant in the context of the future mitigation of impact hazard from these dark and dangerous projectiles.
J.M.T.R. and S.T. acknowledge financial support from the Spanish Ministry (PGC2018-097374-B-I00, PI: JMTR). J.L.L. is grateful to ICREA Academia program and funding from Generalitat de Catalunya (2017 SGR 128). US Antarctic meteorite samples are recovered by the Antarctic Search for Meteorites (ANSMET) program which has been funded by NSF and NASA, and characterized and curated by the Department of Mineral Sciences of the Smithsonian Institution and Astromaterials Acquisition and Curation Office at NASA Johnson Space Center.