A1 Refereed original research article in a scientific journal
Searching for calcium-aluminum-rich inclusions in cometary particles with Rosetta/COSIMA
Authors: Paquette JA, Engrand C, Stenzel O, Hilchenbach M, Kissel J, the COSIMA Team
Publisher: WILEY-BLACKWELL
Publication year: 2016
Journal: Meteoritics and Planetary Science
Journal name in source: METEORITICS & PLANETARY SCIENCE
Journal acronym: METEORIT PLANET SCI
Volume: 51
Issue: 7
First page : 1340
Last page: 1352
Number of pages: 13
ISSN: 1086-9379
eISSN: 1945-5100
DOI: https://doi.org/10.1111/maps.12669
Abstract
The calcium-aluminum-rich inclusions (CAIs) found in chondritic meteorites are probably the oldest solar system solids, dating back to 4567.30 +/- 0.16 million years ago. They are thought to have formed in the protosolar nebula within a few astronomical units of the Sun, and at a temperature of around 1300K. The Stardust mission found evidence of CAI-like material in samples recovered from comet Wild 2. The appearance of CAIs in comets, which are thought to be formed at lower temperatures and larger distances from the Sun, is only explicable if some mechanism allows the efficient transfer of such objects from the inner solar nebula to the outer solar nebula. Such mechanisms have been proposed such as an X-wind or turbulence. In this work, particles collected from within the coma of comet 67P/Churyumov-Gerasimenko are examined for compositional evidence of the presence of CAIs. COSIMA (the Cometary Secondary Ion Mass Analyzer) uses secondary ion mass spectrometry to analyze the composition of cometary dust captured on metal targets. While CAIs can have a radius of centimeters, they are more typically a few hundred microns in size, and can be smaller than 1m, so it is conceivable that particles visible on COSIMA targets (ranging in size from about 10m to hundreds of microns) could contain CAIs. Using a peak fitting technique, the composition of a set of 13 particles was studied, looking for material rich in both calcium and aluminum. One such particle was found.
The calcium-aluminum-rich inclusions (CAIs) found in chondritic meteorites are probably the oldest solar system solids, dating back to 4567.30 +/- 0.16 million years ago. They are thought to have formed in the protosolar nebula within a few astronomical units of the Sun, and at a temperature of around 1300K. The Stardust mission found evidence of CAI-like material in samples recovered from comet Wild 2. The appearance of CAIs in comets, which are thought to be formed at lower temperatures and larger distances from the Sun, is only explicable if some mechanism allows the efficient transfer of such objects from the inner solar nebula to the outer solar nebula. Such mechanisms have been proposed such as an X-wind or turbulence. In this work, particles collected from within the coma of comet 67P/Churyumov-Gerasimenko are examined for compositional evidence of the presence of CAIs. COSIMA (the Cometary Secondary Ion Mass Analyzer) uses secondary ion mass spectrometry to analyze the composition of cometary dust captured on metal targets. While CAIs can have a radius of centimeters, they are more typically a few hundred microns in size, and can be smaller than 1m, so it is conceivable that particles visible on COSIMA targets (ranging in size from about 10m to hundreds of microns) could contain CAIs. Using a peak fitting technique, the composition of a set of 13 particles was studied, looking for material rich in both calcium and aluminum. One such particle was found.
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