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Silicon carbide: The problem with laboratory spectra

Speck, AK; Hofmeister, AM; Barlow, MJ; (2000) Silicon carbide: The problem with laboratory spectra. In: Sitko, ML and Sprague, AL and Lynch, DK, (eds.) Volume: 196, Thermal Emission Spectroscopy and Analysis of Dust, Disks, and Regoliths. (pp. pp. 281-290). Astronomical Society of the Pacific Green open access

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Abstract

The interpretation of astronomical observations of infrared (IR) silicon carbide (SiC) features in the spectra of carbon stars have revealed discrepancies between the work of astronomers and that of meteoriticists. The silicon carbide observed around carbon stars has been attributed to one type of SiC (α) while meteoritic samples believed to have formed around such stars are of another type of SiC (β). The key to solving this problem has been to understand the sources of laboratory data used by astronomers in order to interpret the IR spectra. Through comparison of thin film IR absorption spectra and spectra taken using finely ground samples dispersed in potassium bromide (KBr) pellets we show that the previously invoked ``KBr matrix-correction'' is unnecessary for powder dispersions obtained from very fine grain sizes of SiC. Comparison of our data and previous measurements show that dust around carbon stars is β-SiC, consistent with laboratory studies of presolar grains in meteorites. The implications of these findings affect twenty years of work. The IR spectroscopic laboratory data used by astronomers to identify dust species in space must be carefully scrutinized to ensure that the KBr correction is not responsible for further misattributions of minerals in astronomical dust features.

Type: Proceedings paper
Title: Silicon carbide: The problem with laboratory spectra
Event: Meeting on Thermal Emission Spectroscopy and Analysis of Dust, Disks, and Regoliths
Location: LUNAR & PLANETARY INST, HOUSTON, TX
Dates: 28 April 1999 - 30 April 1999
ISBN: 1-58381-023-4
Open access status: An open access version is available from UCL Discovery
Publisher version: Volume: 196, Thermal Emission Spectroscopy and Ana...
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Science & Technology, Physical Sciences, Astronomy & Astrophysics, GRAINS
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI: https://discovery.ucl.ac.uk/id/eprint/10096055
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