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Reanalysis of the Benesov bolide and recovery of polymict breccia meteorites - old mystery solved after 20 years
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SYSNO ASEP 0434829 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Reanalysis of the Benesov bolide and recovery of polymict breccia meteorites - old mystery solved after 20 years Author(s) Spurný, Pavel (ASU-R) ORCID, RID
Haloda, J. (CZ)
Borovička, Jiří (ASU-R) RID, ORCID
Shrbený, Lukáš (ASU-R) RID, ORCID
Halodová, P. (CZ)Source Title Astronomy & Astrophysics. - : EDP Sciences - ISSN 0004-6361
Roč. 570, October (2014), A39/1-A39/14Number of pages 14 s. Publication form Print - P Language eng - English Country FR - France Keywords meteorites ; meteors ; meteoroids Subject RIV BN - Astronomy, Celestial Mechanics, Astrophysics R&D Projects GA205/08/0411 GA ČR - Czech Science Foundation (CSF) GAP209/11/1382 GA ČR - Czech Science Foundation (CSF) Institutional support ASU-R - RVO:67985815 UT WOS 000344158500098 DOI https://doi.org/10.1051/0004-6361/201424308 Annotation The main motivation for this work was to explain and solve the old mystery connected with the detailed instrumental observation of the Benešov superbolide on 7 May 1991 over the central part of the Czech Republic. In spring 2011, we remeasured all available records and reanalyzed the data. We used slightly different methods and new approaches, which we gradually developed to analyze several recent instrumentally observed meteorite falls. We assembled a new consistent picture of the Benešov event, which resulted in a slightly revised impact location and suggested a new strategy that might lead to a recovery of Benešov meteorites after 20 years. The reality completely confirmed all our assumptions and surpassed our expectations. We found four small highly weathered fragments with a total mass of 11.63 g (1.54 g (H5), 7.72 g (with achondritic clast), 1.99 g, 0.38 g (all LL3.5)). They were recovered exactly in the predicted impact area for corresponding masses, namely within 40 m from the highest probability line. Although all fragments are very small and their weathering grade is high (W3 for all pieces), their interior was preserved enough for reliable analysis (except for the smallest one). The meteorite is classified as a polymict breccia containing three recognized lithologies with different texture, chemical, and mineralogical composition. This result is pioneering in many aspects. We proved that in some special cases it is still possible to predict and find meteorites a long time after the fall. The most important result, however, is the heterogeneity of the recovered meteorites. This case clearly shows that larger meteoroids can be compositionally very complicated bodies. We discovered that the Benešov meteoroid consisted of at least three different types of material – LL3.5, H5, and primitive achondrite. This case also implies that it is very useful to study as many fragments as possible from one fall because there can be significant differences among them. Workplace Astronomical Institute Contact Anežka Melichárková, bibl@asu.cas.cz, Tel.: 323 620 326 Year of Publishing 2015
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