Rudraswami, NG, Shyam Prasad, M, Dey, S et al. (5 more authors) (2016) Relict of Olivines in Micrometeorites: Precursors and interactions in the Earth's atmosphere. Astrophysical Journal, 831 (2). ISSN 0004-637X
Abstract
Antarctica micrometeorites (~1200) and cosmic spherules (~5000) from deep sea sediments are studied using electron microscopy to identify Mg-rich olivine grains in order to determine the nature of the particle precursors. Mg-rich olivine (FeO < 5wt%) in micrometeorites suffers insignificant chemical modification during its history and is a well-preserved phase. 420 forsterite grains enclosed in 162 micrometeorites of different types - unmelted, scoriaceous and porphyritic - are examined in this study. Forsterites in micrometeorites of different types are crystallized during their formation in solar nebula; their closest analogues are chondrule components of CV-type chondrites or volatile rich CM chondrites. The forsteritic olivines are suggested to have originated from a cluster of closely related carbonaceous asteroids that have Mg-rich olivines in the narrow range of CaO (0.1−0.3 wt%), Al2O3 (0.0−0.3wt%), MnO (0.0−0.3wt%) and Cr2O3 (0.1−0.7wt%). Numerical simulations carried out with the Chemical Ablation Model (CABMOD) enable us to define the physical conditions of atmospheric entry that preserve the original compositions of the Mg-rich olivines in these particles. The chemical compositions of relict olivines affirm the role of heating at peak temperatures and the cooling rates of the micrometeorites. This modelling approach provides a foundation for understanding the ablation of the particles and the circumstances in which the relict grains tend to survive.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016. The American Astronomical Society. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | atmospheric effects, Earth, interplanetary medium , minor planets, asteroids: general, Sun: general |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Physical Chemistry (Leeds) |
Funding Information: | Funder Grant number NERC NE/L01243X/1 UK Space Agency RP10G0327C11/B11 Royal Society 2006/R1 Royal Society 2005/R2 NERC NE/D006562/1 NERC NE/D006287/1 NERC NE/E005659/1 NERC NE/B00015X/2 NERC NE/D002060/1 Royal Society 2007/R4 EOARD - US AirForce 093015 NERC NCAS AGREEMENT NERC NE/G019487/1 EOARD - US AirForce FA8655-10-1-3045 Royal Society TG101145 - 2010/R2 Leverhulme Trust F/00 122/BB NERC NE/J008621/1 NERC NE/J02077X/1 Royal Astronomical Society . NERC NE/J008621/1 NERC NE/J008621/1 Science & Technology Facilities Council (STFC) ST/L000628/1 NERC no ext. ref. NERC NCAS 15/16 NERC No External Reference NERC R8/H12/83/013 Centre for Earth Observation Instrumentation 4600 |
Depositing User: | Symplectic Publications |
Date Deposited: | 09 Sep 2016 12:39 |
Last Modified: | 05 Oct 2017 16:11 |
Published Version: | https://doi.org/10.3847/0004-637X/831/2/197 |
Status: | Published |
Publisher: | American Astronomical Society |
Identification Number: | 10.3847/0004-637X/831/2/197 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:104523 |