Annama H chondrite-Mineralogy, physical properties, cosmic ray exposure, and parent body history

作者：Kohout Tomas^*; Haloda Jakub; Halodova Patricie; Meier Matthias M M; Maden Colin; Busemann Henner; Laubenstein Matthias; Caffee Marc W; Welten Kees C; Hopp Jens; Trieloff Mario; Mahajan Ramakant R; Naik Sekhar; Trigo Rodriguez Josep M; Moyano Cambero Carles E; Oshtrakh Michael I; Maksimova Alevtina A; Chukin Andrey V; Semionkin Vladimir A; Karab****ov Maksim S; Felner Israel; Petrova Evgeniya V; Brusnitsyna Evgeniia V; Grokhovsky Victor I

来源：Meteoritics & Planetary Science, 2017, 52(8): 1525-1541.

DOI：10.1111/maps.12871

The fall of the Annama meteorite occurred early morning (local time) on April 19, 2014 on the Kola Peninsula (Russia). Based on mineralogy and physical properties, Annama is a typical H chondrite. It has a high Ar-Ar age of 4.4 Ga. Its cosmic ray exposure history is atypical as it is not part of the large group of H chondrites with a prominent 7-8 Ma peak in the exposure age histograms. Instead, its exposure age is within uncertainty of a smaller peak at 30 +/- 4 Ma. The results from short-lived radionuclides are compatible with an atmospheric pre-entry radius of 30-40 cm. However, based on noble gas and cosmogenic radionuclide data, Annama must have been part of a larger body (radius >65 cm) for a large part of its cosmic ray exposure history. The Be-10 concentration indicates a recent (3-5 Ma) breakup which may be responsible for the Annama parent body size reduction to 30-35 cm pre-entry radius.

• 出版日期2017-8