Thermal infrared and optical observations of four near-Earth asteroids

Wolters, S. D.; Green, Simon; McBride, Neil; Davies, John K.

doi:10.1016/j.icarus.2007.08.011

Cited by 36 publications

(54 citation statements)

References 43 publications

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“…In fact, the difference in instrument scale factors between the two datasets explain the difference in diameters obtained by the previously published NEATM fitting, i.e. 20.4 km for Lim et al (2005) and 23.3 km for Wolters et al (2008). This suggests that the Wolters et al (2008) observations could have been affected by external environmental factors and could be anomalous.…”

Section: Resultsmentioning

confidence: 81%

“…However, the fit to the Wolters et al (2008) dataset produces a much smaller degree of surface roughness, which is apparent by the cooler colour temperature of the dataset's thermal spectrum. This is surprising considering that this thermal spectrum was taken at very similar geometry and rotation phase to the 3rd spectrum of Lim et al (2005).…”

Section: Resultsmentioning

confidence: 99%

“…Harris & Davies (1999), Lim et al (2005), and Wolters et al (2008) all used the NEATM thermal model of Harris (1998) to fit their data and obtained effective diameters that ranged from 20.4 to 23.6 km, and NEATM beaming parameters that ranged from 0.7 to 1.07. From their derived NEATM beaming parameter value, Harris & Davies (1999) .…”

Section: Asteroid (433) Erosmentioning

confidence: 99%

“…The Lim et al (2005) dataset consists of 3 spectra taken at 3 different rotation phases (see Table 1), and the Wolters et al (2008) dataset, which was obtained a week later, consists of 1 spectrum taken at a similar rotation phase to the 3rd spectrum of Lim et al (2005). Both datasets are publicly available.…”

Section: Thermal-infrared Flux Fittingmentioning

confidence: 99%

“…Both datasets are publicly available. The Lim et al (2005) dataset contains 42 wavelengths between 8 and 13 μm per spectrum, and the Wolters et al (2008) dataset contains 13 wavelengths between the same range. In this work, each spectrum is fitted independently by the ATPM to look for any spatial variations in surface roughness across Eros.…”

Section: Thermal-infrared Flux Fittingmentioning

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: Resultsmentioning

confidence: 81%

Section: Resultsmentioning

confidence: 99%