Atlas of reflectance spectra of terrestrial, lunar, and meteoritic powders and frosts from 92 to 1800 nm

Wagner, J. K.; Hapke, Bruce; Wells, Edward F.

doi:10.1016/0019-1035(87)90003-0

Cited by 138 publications

(141 citation statements)

References 22 publications

Supporting

Mentioning

133

Contrasting

Order By: Relevance

“…In the 1400−1800 Å wavelength region, a slight blue slope would be expected if water ice existed on the surface, due to a broad water ice absorption band centered around 1600 Å in the FUV. However, if water ice were detected with Alice, at the longer wavelengths beyond 1800 Å, outside of the absorption band, we should see a rise in the bidirectional reflectance of 67P (Hapke et al 1981;Wagner et al 1987;Hendrix & Hansen 2008), which we do not. In fact, the spectra presented here do not show indications of any absorption features or absorption edges.…”

Section: Discussioncontrasting

confidence: 57%

“…This is considered to be blue sloped because of the decrease with increasing wavelength and is consistent with the derived values of the single scattering albedo, w, which also decreases from 1425−1525 Å to 1700−1800 Å (Table 3). While a blue slope may be suggestive of water ice on the surface in this finite FUV region as seen in the laboratory (Hapke et al 1981;Wagner et al 1987), using Hapke modeling as in Hendrix & Hansen (2008) it has also been shown that the water ice spectrum is expected to have a red slope at these wavelengths due to the location of the edge of the FUV cut-off if water ice were present. Therefore, the FUV blue slope alone is inconclusive with respect to the presence of water ice.…”

Section: Photometric Correctionmentioning

confidence: 81%

See 1 more Smart Citation

Far-UV phase dependence and surface characteristics of comet 67P/Churyumov-Gerasimenko as observed with Rosetta Alice

Feaga

Protopapa

Schindhelm

et al. 2015

A&A

View full text Add to dashboard Cite

Aims. The Alice far-ultraviolet (FUV) spectrograph onboard Rosetta has, for the first time, imaged the surface of a comet, 67P/Churyumov-Gerasimenko (67P), in the FUV. With spatially resolved data, the nucleus properties are characterized in the FUV, including phase dependence, albedo, and spectral slope. Regional measurements across the nucleus are compared to discern any compositional variations. Methods. Hapke theory was utilized to model the phase dependence of the material on the surface of 67P. The phase dependence of 67P was derived from a subset of data acquired at various phase angles in November 2014, within 50 km of the comet such that the nucleus was spatially resolved. The derived photometric correction was then applied to a different subset of spatially resolved data sampling several distinct geographical regions on the nucleus acquired in August−November 2014 under similar viewing geometries. Results. In the FUV, the surface of 67P is dark, blue sloped, has an average geometric albedo of 0.054 ± 0.008 at 1475 Å near the center of the Alice bandpass, and is mostly uniform from region to region, with the exception of the Hatmehit region, which is slightly more reflective. These results are consistent with the suggestion made by the Rosetta OSIRIS and VIRTIS teams that the surface of 67P is covered with a homogeneous layer of material and that surface ice is not ubiquitous in large abundances. The modeled Hapke parameters, specifically the single scattering albedo (w) and the asymmetry factor (ζ), are determined to be 0.031 ± 0.003 and −0.530 ± 0.025 near the center of the Alice bandpass at 1475 Å. These parameters are consistent with measurements of other comet nuclei that have been observed by flyby missions in the visible and the near-infrared regimes.

show abstract

Section: Discussioncontrasting

confidence: 57%

Section: Photometric Correctionmentioning

confidence: 81%

Far-UV phase dependence and surface characteristics of comet 67P/Churyumov-Gerasimenko as observed with Rosetta Alice

Feaga

Protopapa

Schindhelm

et al. 2015

A&A

View full text Add to dashboard Cite

show abstract

“…The relative values of the ratios show that Pele is the darkest and Ra the brightest of the three targets in this wavelength region, which is similar to the reflectivities of these three regions in somewhat longer-wavelength UV imaging observations (Sartoretti et al 1996). λ 2400Å by Hapke et al (1981) and Wagner et al (1987) are in reasonable agreement, they disagree in absolute value with the more detailed laboratory measurements by Nash et al (1980) by approximately a factor of 5 (depending on the frost grain size assumed) at 2400Å. The Hapke-Wagner results are therefore generally scaled down to match the Nash et al value.…”

Section: Surface Reflectancementioning

confidence: 55%

“…(3) The overall shape of the Ra/Pele ratio spectrum ( Fig. 5b) matches well the reflectivity of SO 2 frost, which we have overplotted on the ratio using the measured frost reflectance of Wagner et al (1987).…”

Section: Modeling and Analysismentioning

confidence: 64%

Spatially Resolved Spectroscopy of Io's Pele Plume and SO2 Atmosphere

McGrath¹

2000

Icarus

View full text Add to dashboard Cite

“…Perhaps some mixture of samples could be found to approximate Lutetia's spectrum, but such an effort is beyond the scope of this paper. We note, however, that many of the materials measured by Wagner et al (1987) have spectral features shortward of 2000 Å, which are potentially observable by the Alice instrument during the Rosetta flyby.…”

Section: Discussionmentioning

confidence: 82%

Ultraviolet and visible photometry of asteroid (21) Lutetia using the Hubble Space Telescope

Weaver¹,

Feldman²,

Merline³

et al. 2010

A&A

View full text Add to dashboard Cite

Context. The asteroid (21) Lutetia is the target of a planned close encounter by the Rosetta spacecraft in July 2010. To prepare for that flyby, Lutetia has been extensively observed by a variety of astronomical facilities. Aims. We used the Hubble Space Telescope (HST) to determine the albedo of Lutetia over a wide wavelength range, extending from ∼1500 Å to ∼7000 Å. Methods. Using data from a variety of HST filters and a ground-based visible light spectrum, we employed synthetic photometry techniques to derive absolute fluxes for Lutetia. New results from ground-based measurements of Lutetia's size and shape were used to convert the absolute fluxes into albedos. Results. We present our best model for the spectral energy distribution of Lutetia over the wavelength range 1200−8000 Å. There appears to be a steep drop in the albedo (by a factor of ∼2) for wavelengths shorter than ∼3000 Å. Nevertheless, the far ultraviolet albedo of Lutetia (∼10%) is considerably larger than that of typical C-chondrite material (∼4%). The geometric albedo at 5500 Å is 16.5 ± 1%. Conclusions. Lutetia's reflectivity is not consistent with a metal-dominated surface at infrared or radar wavelengths, and its albedo at all wavelengths (UV-visibile-IR-radar) is larger than observed for typical primitive, chondritic material. We derive a relatively high FUV albedo of ∼10%, a result that will be tested by observations with the Alice spectrograph during the Rosetta flyby of Lutetia in July 2010.

show abstract

Atlas of reflectance spectra of terrestrial, lunar, and meteoritic powders and frosts from 92 to 1800 nm

Cited by 138 publications

References 22 publications

Far-UV phase dependence and surface characteristics of comet 67P/Churyumov-Gerasimenko as observed with Rosetta Alice

Far-UV phase dependence and surface characteristics of comet 67P/Churyumov-Gerasimenko as observed with Rosetta Alice

Spatially Resolved Spectroscopy of Io's Pele Plume and SO2 Atmosphere

Ultraviolet and visible photometry of asteroid (21) Lutetia using the Hubble Space Telescope

Contact Info

Product

Resources

About