Spectral Reflectance Properties of Carbon-Bearing Materials

Cloutis, E. A.; Gaffey, M. J.; Moslow, Thomas F.

doi:10.1006/icar.1994.1023

Cited by 47 publications

(30 citation statements)

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“…On the basis of laboratory spectra of a suite of natural terrestrial organic solids by Cloutis (1989) and Moroz et In the photovisual spectral region, as Moroz et al (1991Moroz et al ( , 1992 and Cloutis et al (1994) found, the presence of both al. (1991,1992), Cruikshank et al (1993) proposed that the red color and the 2.27-Ȑm absorption band of Pholus might aliphatic and aromatic groups is needed to give the red colors of the asphaltite-like organics, but variations in the be matched by similar features shown by those materials.…”

Section: The Asphaltite Modelmentioning

confidence: 89%

The Composition of Centaur 5145 Pholus

Cruikshank

Roush

Bartholomew

et al. 1998

Icarus

244

199

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Section: The Asphaltite Modelmentioning

confidence: 89%

The Composition of Centaur 5145 Pholus

Cruikshank

Roush

Bartholomew

et al. 1998

Icarus

244

199

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“…3) of the imaginary refractive index, k, of the two tholins we used will show that there is no significant absorption in either one of them at 1.8 µm. Solid hydrocarbon complexes have combination and overtone bands in this region, with the first overtones and combinations of -CH 2 and -CH 3 occurring in the 1.69-1.76 µm region in terrestrial bitumins (Cloutis et al, 1994;Moroz et al, 1998). Complex hydrocarbons may indeed be present on Hyperion, contributing to its lower albedo than most of Saturn's other icy satellites.…”

Section: Hyperionmentioning

confidence: 99%

A spectroscopic study of the surfaces of Saturn's large satellites: HO ice, tholins, and minor constituents

Cruikshank¹,

Owen²,

Ore³

et al. 2005

Icarus

100

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We present spectra of Saturn's icy satellites Mimas, Enceladus, Tethys, Dione, Rhea, and Hyperion, 1.0-2.5 µm, with data extending to shorter (Mimas and Enceladus) and longer (Rhea and Dione) wavelengths for certain objects. The spectral resolution (R = λ/ λ) of the data shown here is in the range 800-1000, depending on the specific instrument and configuration used; this is higher than the resolution (R = 225 at 3 µm) afforded by the Visual-Infrared Mapping Spectrometer on the Cassini spacecraft. All of the spectra are dominated by water ice absorption bands and no other features are clearly identified. Spectra of all of these satellites show the characteristic signature of hexagonal H 2 O ice at 1.65 µm. We model the leading hemisphere of Rhea in the wavelength range 0.3-3.6 µm with the Hapke and the Shkuratov radiative transfer codes and discuss the relative merits of the two approaches to fitting the spectrum. In calculations with both codes, the only components used are H 2 O ice, which is the dominant constituent, and a small amount of tholin (Ice Tholin II). Tholin in small quantities (few percent, depending on the mixing mechanism) appears to be an essential component to give the basic red color of the satellite in the region 0.3-1.0 µm. The quantity and mode of mixing of tholin that can produce the intense coloration of Rhea and other icy satellites has bearing on its likely presence in many other icy bodies of the outer Solar System, both of high and low geometric albedos. Using the modeling codes, we also establish detection limits for the ices of CO 2 (a few weight percent, depending on particle size and mixing), CH 4 (same), and NH 4 OH (0.5 weight percent) in our globally averaged spectra of Rhea's leading hemisphere. New laboratory spectral data for NH 4 OH are presented for the purpose of detection on icy bodies. These limits for CO 2 , CH 4 , and NH 4 OH on Rhea are also applicable to the other icy satellites for which spectra are presented here. The reflectance spectrum of Hyperion shows evidence for a broad, unidentified absorption band centered at 1.75 µm.

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“…Diamonds are not black, even though they are composed of nearly pure elemental carbon. Natural graphite re ects ten times the visible light of synthetic black carbon and more than twice that of coal and tar (Cloutis et al 1994).…”

Section: Introductionmentioning

confidence: 99%

Comparison of IMPROVE and NIOSH Carbon Measurements

Chow

Watson

Crow

et al. 2001

Aerosol Science and Technology

227

344

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Organic carbon (OC) and elemental carbon (EC) are operationally de ned by the analysis methods, and different methods give in different results. The IMPROVE (Interagency Monitoring of Protected Visual Environments) and NIOSH (National Institute of Occupational Safety and Health) thermal evolution protocols present different operational de nitions. These protocols are applied to 60 ambient and source samples from different environments using the same instrument to quantify differences in implemented protocols on the same instrument. The protocols are equivalent for total carbon sampled on quartz-ber lters. NIOSH EC was typically less than half of IMPROVE EC. The primary difference is the allocation of carbon evolving at the NIOSH 850 ± C temperature in a helium atmosphere to the OC rather than EC fraction. Increasing light transmission and re ectance during this temperature step indicate that this fraction should be classi ed as EC. When this portion of NIOSH OC is added to NIOSH EC, the IMPROVE and NIOSH analyses are in good agreement. The most probable explanation is that mineral oxides in the complex particle mixture on the lter are supplying oxygen to neighboring carbon particles at this high temperature. This has been demonstrated by the principle of the thermal manganese oxidation method that is also commonly used to distinguish OC from EC. For both methods, the optical pyrolysis adjustment to the EC fractions was always higher for transmittance than for re ectance. This is a secondary cause of differences between the two methods, with transmittance resulting in a lower EC loading than re ectance. The difference was most pronounced for very black lters on which neither re ectance nor transmittance accurately detected further blackening due to pyrolysis.

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Spectral Reflectance Properties of Carbon-Bearing Materials

Cited by 47 publications

References 0 publications

The Composition of Centaur 5145 Pholus

The Composition of Centaur 5145 Pholus

A spectroscopic study of the surfaces of Saturn's large satellites: HO ice, tholins, and minor constituents

Comparison of IMPROVE and NIOSH Carbon Measurements

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