Ein Vergleich (pre-rain SM2 und post-rain SM12 and SM51) zur Beschreibung der terrestrischen Kontamination mit Aminosäuren. Man kann diese Ergebnisse auch indirekt als wissenschaftliches Plädoyer für sehr schnelle kooperative Anstrengungen zum Auffinden und Sicherstellen frisch gefallener Meteorite lesen. Ähnliche Bemühungen der Einbindung qualifizierter Amateure sehen wir in den letzten Tagen durch Phil McCausland (University of Western Ontario) bei der Meteoritensuche um Aylmer und St. Thomas in Ontario, Kanada (Meteor vom 18. März (~22.24 Uhr Ortszeit) / siehe auch Radiointerview mit Phil McCausland unten)
The amino acid composition of the Sutter's Mill CM2 carbonaceous chondriteAaron S. Burton, Daniel P. Glavin, Jamie E. Elsila, Jason P. Dworkin, Peter Jenniskens and Qing-Zhu Yin
Meteoritics & Planetary Science, article first published online: 22 MAR 2014 ; DOI: 10.1111/maps.12281
LINKAbstract
We determined the abundances and enantiomeric compositions of amino acids in Sutter's Mill fragment #2 (designated SM2) recovered prior to heavy rains that fell April 25–26, 2012, and two other meteorite fragments, SM12 and SM51, that were recovered postrain. We also determined the abundance, enantiomeric, and isotopic compositions of amino acids in soil from the recovery site of fragment SM51. The three meteorite stones experienced terrestrial amino acid contamination, as evidenced by the low d/l ratios of several proteinogenic amino acids. The d/l ratios were higher in SM2 than in SM12 and SM51, consistent with rain introducing additional l-amino acid contaminants to SM12 and SM51. Higher percentages of glycine, β-alanine, and γ-amino-n-butyric acid were observed in free form in SM2 and SM51 compared with the soil, suggesting that these free amino acids may be indigenous. Trace levels of d+l-β-aminoisobutyric acid (β-AIB) observed in all three meteorites are not easily explained as terrestrial contamination, as β-AIB is rare on Earth and was not detected in the soil. Bulk carbon and nitrogen and isotopic ratios of the SM samples and the soil also indicate terrestrial contamination, as does compound-specific isotopic analysis of the amino acids in the soil. The amino acid abundances in SM2, the most pristine SM meteorite analyzed here, are approximately 20-fold lower than in the Murchison CM2 carbonaceous chondrite. This may be due to thermal metamorphism in the Sutter's Mill parent body at temperatures greater than observed for other aqueously altered CM2 meteorites.
Search continues for St. Thomas meteoritesAUDIO (The Morning Edition, Kitchener Waterloo, CBC, 24.3.2014)
Professor Phil McCausland von der University of Western Ontario berichtet über die Meteoritensuche in der Nähe von Aylmer und St. Thomas, Ontario, Canada am letzten Woche.
Gesucht werden Meteorite des großen Meteors vom 18. März (~22.24 Uhr Ortszeit), der von sieben All-Sky-Cams des Western's Southern Ontario Meteor Network (SOMN) aufgenommen wurde. Der Verlöschungspunkt soll sich in einer Höhe von 32 km befunden haben.
