Near-IR Reflectance Spectroscopy of 433 Eros from the NIS Instrument on the NEAR Mission

Bell, J. F.; Izenberg, N. R.; Lucey, P. G.; Clark, B. E.; Peterson, C.; Gaffey, M. J.; Joseph, J.; Carcich, B.; Harch, A.; Bell, Maureen; Warren, J.; Martin, Patrick; McFadden, L. A.; Wellnitz, D. D.; Murchie, S. L.; Winter, Michael E.; Veverka, J.; Thomas, P. C.; Robinson, M. S.; Malin, M. C.; Cheng, A. F.

doi:10.1006/icar.2001.6752

Cited by 71 publications

(61 citation statements)

References 49 publications

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“…(433) Eros is the second largest near-Earth asteroid (hereafter referred to as Eros), is an S-type asteroid, and was the target of NASA's NEAR Shoemaker mission (Cheng 2002 Bussey et al 2002), more than 200,000 spatially resolved near infrared reflectance spectra (NIS; Bell et al 2002), and more than 16 million laser range measurements (NLR; Cheng et al 2002). The MSI images had resolutions ranging from 3 to 19 m per pixel, which revealed an irregular shaped body with many craters and evidence of a surface regolith.…”

Section: Asteroid (433) Erosmentioning

confidence: 99%

“…The images and continuity of the shape model also indicated that Eros was a solid body throughout and not a loose rubble-pile. The NIS measurements revealed a small variation in albedo across the surface of Eros after photometric corrections were made to correct for the differing viewing geometries (Bell et al 2002;Clark et al 2002). Brighter regions were thought to represent fresher and less altered material, whereas darker regions were thought to represent more space weathered material.…”

Section: Asteroid (433) Erosmentioning

confidence: 99%

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The surface roughness of (433) Eros as measured by thermal-infrared beaming

Rozitis

2016

Mon. Not. R. Astron. Soc.

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In planetary science, surface roughness is regarded to be a measure of surface irregularity at small spatial scales, and causes the thermal-infrared beaming effect (i.e. re-radiation of absorbed sunlight back towards to the Sun). Typically, surface roughness exhibits a degeneracy with thermal inertia when thermophysical models are fitted to disc-integrated thermal-infrared observations of asteroids because of this effect. In this work, it is demonstrated how surface roughness can be constrained for near-Earth asteroid (433) Eros (i.e. the target of NASA's NEAR Shoemaker mission) when using the Advanced Thermophysical Model with thermal-infrared observations taken during an "almost poleon" illumination and viewing geometry. It is found that the surface roughness of (433) Eros is characterised by an RMS slope of 38 ± 8° at the 0.5-cm spatial scale associated with its thermalinfrared beaming effect. This is slightly greater than the RMS slope of 25 ± 5° implied by the NEAR Shoemaker laser ranging results when extrapolated to this spatial scale, and indicates that other surface shaping processes might operate, in addition to collisions and gravity, at spatial scales under one metre in order to make asteroid surfaces rougher. For other high obliquity asteroids observed during "pole-on" illumination conditions, the thermal-infrared beaming effect allows surface roughness to be constrained when the sub-solar latitude is greater than 60°, and if the asteroids are observed at phase angles of less than 40°. They will likely exhibit NEATM beaming parameters that are lower than expected for a typical asteroid at all phase angles up to 100°.

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Section: Asteroid (433) Erosmentioning

confidence: 99%

Section: Asteroid (433) Erosmentioning

confidence: 99%

The surface roughness of (433) Eros as measured by thermal-infrared beaming

Rozitis

2016

Mon. Not. R. Astron. Soc.

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“…There has been a long-standing controversy over whether or not many S-type asteroids are the parent bodies of ordinary chondrites, but with a surface that has been altered in the space environment. The issue has been settled by gradual accumulating telescopic data for small asteroids with good spatial and spectral resolution (Binzel et al 1996(Binzel et al , 2004 as well as detailed compositional studies linking S-asteroids and ordinary chondrites during rendezvous of Eros by NEAR (McCoy et al 2001;Cheng 2002;Bell et al 2002) and asteroid 25143 Itokawa by Hyabusa (Binzel et al 2001;Ishiguro et al 2007). Reports on analyses of Itokawa material returned to Earth were presented at the Lunar and Planetary Science Conference in Houston (March, 2011) and showed that indeed Itokawa is composed of LL chondritic material with several particles exhibiting the presence of small amounts of a nanophase metal-rich component indicating spaceweathering.…”

Section: Spwe: Backgroundmentioning

confidence: 99%

Surface Composition of Vesta: Issues and Integrated Approach

et al. 2011

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The instruments on the Dawn spacecraft are exceptionally well suited to characterize and map the surface composition of Vesta in an integrated manner. These include a framing camera with multispectral capabilities, a high spectral resolution near-infrared imaging spectrometer, and a gamma-ray and neutron spectrometer. Three examples of issues addressed at Vesta are: (1) What is the composition of Vesta's interior and differentiation state as exposed by the Great South Crater? (2) How has space weathering affected Vesta, both globally and at a local scale? and (3) Are volatiles or hydrated material present on Vesta's surface? We predict that Dawn finds many surprises, such as an olivine-bearing mantle exposed near the south-pole, a weakly or un-weathered surface that has been rela- tively recently resurfaced, and a very thin layer of surficial volatiles derived from interaction with the solar wind.

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“…They conclude that phase reddening corrections cannot be ignored for a proper comparison between NEAs and Main Belt asteroids. A study of the dependency of the reflectance on the phase angle was made during the approach to (433) Eros by the NEAR spacecraft (Veverka et al 2000;Bell et al 2002;Clark et al 2002b). These studies as well find a clear presence of phase reddening.…”

Section: Resultsmentioning

confidence: 99%

Spectroscopy of near-Earth asteroids

Michelsen

Nathues

Lagerkvist³

2006

A&A

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We present spectra and taxonomic classifications of 12 Near-Earth Asteroids (NEAs) and 2 inner Main Belt asteroids. The observations were carried out with the ESO 3.5 m NTT and the Danish 1.54 m telescope at La Silla, Chile. Eleven of the investigated NEAs belong to the S class while only one C-type has been identified. Two NEAs were observed at phase angles larger than 60 • introducing significant phase reddening. In order to allow for comparisons between spectra of asteroids observed at different phase angles we make attempts to correct for this effect. However, it turned out that a uniform approach based on previous measurements of phase reddening by means of observational data is not reasonable. For the NEAs we question the approach of taxonomic classification in terms of subgroups, when the classification is based on spectra obtained at large phase angles.

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Near-IR Reflectance Spectroscopy of 433 Eros from the NIS Instrument on the NEAR Mission

Cited by 71 publications

References 49 publications

The surface roughness of (433) Eros as measured by thermal-infrared beaming

The surface roughness of (433) Eros as measured by thermal-infrared beaming

Surface Composition of Vesta: Issues and Integrated Approach

Spectroscopy of near-Earth asteroids

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