Extraterrestrial organic compounds and cyanide in the CM2 carbonaceous chondrites Aguas Zarcas and Murchison

1,2José C. Aponte,1,2Hannah L. McLain,1,3Danielle N. Simkus,1Jamie E. Elsila,1Daniel P. Glavin,1Eric T. Parker,1Jason P. Dworkin,4Dolores H. Hill,4,5Harold C. Connolly Jr.,4Dante S. Lauretta
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13531]
1Astrochemistry Laboratory, Code 691, NASA Goddard Space Flight Center, Greenbelt, Maryland, 20771 USA2Department of Chemistry, The Catholic University of America, Washington, District of Columbia, 20064 USA
3NASA Postdoctoral Program at NASA Goddard Space Flight Center, Greenbelt, Maryland, 20771 USA
4Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, 85721 USA

5School of Earth and Environment, Rowan University, Glassboro, New Jersey, 08028 USA
Published by arrangement with John Wiley & Sons

Evaluating the water‐soluble organic composition of carbonaceous chondrites is key to understanding the inventory of organic matter present at the origins of the solar system and the subsequent processes that took place inside asteroid parent bodies. Here, we present a side‐by‐side analysis and comparison of the abundance and molecular distribution of aliphatic amines, aldehydes, ketones, mono‐ and dicarboxylic acids, and free and acid‐releasable cyanide species in the CM2 chondrites Aguas Zarcas and Murchison. The Aguas Zarcas meteorite is a recent fall that occurred in central Costa Rica and constitutes the largest recovered mass of a CM‐type meteorite after Murchison. The overall content of organic species we investigated was systematically higher in Murchison than in Aguas Zarcas. Similar to previous meteoritic organic studies, carboxylic acids were one to two orders of magnitude more abundant than other soluble organic compound classes investigated in both meteorite samples. We did not identify free cyanide in Aguas Zarcas and Murchison; however, cyanide species analyzed after acid digestion of the water‐extracted meteorite mineral matrix were detected and quantified at slightly higher abundances in Aguas Zarcas compared to Murchison. Although there were differences in the total abundances of specific compound classes, these two carbonaceous chondrites showed similar isomeric distributions of aliphatic amines and carboxylic acids, with common traits such as a complete suite of structural isomers that decreases in concentration with increasing molecular weight. These observations agree with their petrologic CM type‐2 classification, suggesting that these meteorites experienced similar organic formation processes and/or conditions during parent body aqueous alteration.

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