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Reflectance spectroscopy of interplanetary dust particles
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| Zeitschriftentitel: | Meteoritics & Planetary Science |
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| Personen und Körperschaften: | , , , |
| In: | Meteoritics & Planetary Science, 31, 1996, 3, S. 394-402 |
| Format: | E-Article |
| Sprache: | Englisch |
| veröffentlicht: |
Wiley
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| Schlagwörter: |
| Zusammenfassung: | <jats:p><jats:bold>Abstract</jats:bold> Reflectance spectra were collected from chondritic interplanetary dust particles (IDPs), a polar micrometeorite, Allende (CV3) meteorite matrix, and mineral standards using a microscope spectrophotometer. Data were acquired over the 380–1100 nm wavelength range in darkfield mode using a halogen light source, particle aperturing diaphrams, and photomultiplier tube (PMT) detectors. Spectra collected from titanium oxide (Ti<jats:sub>4</jats:sub>O<jats:sub>7</jats:sub>), magnetite (Fe<jats:sub>3</jats:sub>O<jats:sub>4</jats:sub>), and Allende matrix establish that it is possible to measure indigenous reflectivities of micrometer‐sized (>5 μm in diameter) particles over the visible (VIS) wavelength range 450–800 nm. Below 450 nm, small particle effects cause a fall‐off in signal into the ultraviolet (UV). Near‐infrared (IR) spectra collected from olivine and pyroxene standards suggest that the ∼1 μm absorption features of Fe‐bearing silicates in IDPs can be detected using microscope spectrophotometry.</jats:p><jats:p>Chondritic IDPs are dark objects (<15% reflectivity) over the VIS 450–800 nm range. Large (>1 μm in diameter) embedded and adhering single mineral grains make IDPs significantly brighter, while surficial magnetite formed by frictional heating during atmospheric entry makes them darker. Most chondritic smooth (CS) IDPs, dominated by hydrated layer silicates, exhibit generally flat spectra with slight fall‐off towards 800 nm, which is similar to type CI and CM meteorites and main‐belt C‐type asteroids. Most chondritic porous (CP) IDPs, dominated by anhydrous silicates (pyroxene and olivine), exhibit generally flat spectra with a slight rise towards 800 nm, which is similar to outer P and D asteroids. The most C‐rich CP IDPs rise steeply towards 800 nm with a redness comparable to that of the outer asteroid object Pholus (Binzel, 1992). Chondritic porous IDPs are the first identified class of meteoritic materials exhibiting spectral reflectivities (between 450 and 800 nm) similar to those of P and D asteroids.</jats:p><jats:p>Although large mineral grains, secondary magnetite, and small particle effects complicate interpretation of IDP reflectance spectra, microscope spectrophotometry appears to offer a rapid, nondestructive technique for probing the mineralogy of IDPs, comparing them with meteorites, investigating their parent body origins, and identifying IDPs that may have been strongly heated during atmospheric entry.</jats:p> |
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| Umfang: | 394-402 |
| ISSN: |
1945-5100
1086-9379 |
| DOI: | 10.1111/j.1945-5100.1996.tb02077.x |