Directional characteristics of thermal–infrared beaming from atmosphereless planetary surfaces – a new thermophysical model

By B. Rozitis, S. Green. 2011

153 citations recorded by the source corpus.

We present a new rough-surface thermophysical model (Advanced Thermophysical Model or ATPM) that describes the observed directional thermal emission from any atmosphereless planetary surface. It explicitly incorporates partial shadowing, scattering of sunlight, self-heating and thermal–infrared beaming (re-radiation of absorbed sunlight back towards the Sun as a result of surface roughness). The model is verified by accurately reproducing ground-based directional thermal emission measurements of the lunar surface using surface properties that are consistent with the findings of the Apollo missions and roughness characterized by an rms slope of ∼32°. By considering the wide range of potential asteroid surface properties, the model implies a beaming effect that cannot be described by a simple parameter or function. It is highly dependent on the illumination and viewing angles as well as surface thermal properties and is predominantly caused by macroscopic rather than microscopic roughness. Roughness alters the effective Bond albedo and thermal inertia of the surface as well as moving the mean emission away from the surface normal. For accurate determination of surface properties from thermal–infrared observations of unresolved bodies or resolved surface elements, roughness must be explicitly modelled, preferably aided with thermal measurements at different emission angles and wavelengths.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/d12c79316a9068d5c2bbaac99035ba68a1a29fda

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In Astronomy and Astrophysics

Citations in the corpus

Density of asteroids (2012, background): “D shape models offer the possibility to analyze thermal radiometry data with more advanced thermal models ( e.g. , Lagerros, 1996, 1997; M¨uller et al., 2005; Mueller et al., 2006; Delbo and Tanga, 2009; Rozitis and Green, 2011; O’Rourke et al., 2012).”
Properties of rubble-pile asteroid (101955) Bennu from OSIRIS-REx imaging and thermal analysis (2019, methodology): “The absolute accuracy of the radiometric calibration is set by the in-flight calibration using images of the Moon taken during the OSIRIS-REx Earth Gravity Assist (EGA).”
Insolation, erosion, and morphology of comet 67P/Churyumov-Gerasimenko (2015, background): “(2) The additional terms Rvis(t) and RIR(t) are the reflected visible and IR contributions, respectively, and E(t) is the emitted temperature-dependent IR input from the facets within the field of view of the reference facet (Rozitis & Green 2011).”