Thermophysical Modeling of Asteroid Surfaces using Ellipsoid Shape Models. (arXiv:1811.02849v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+MacLennan_E/0/1/0/all/0/1">Eric M. MacLennan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Emery_J/0/1/0/all/0/1">Joshua P. Emery</a>
Thermophysical Models (TPMs), which have proven to be a powerful tool in the
interpretation of the infrared emission of asteroid surfaces, typically make
use of a priori obtained shape models and spin axes for use as input boundary
conditions. We test then employ a TPM approach – under an assumption of an
ellipsoidal shape – that exploits the combination of thermal multi-wavelength
observations obtained at pre- and post-opposition. Thermal infrared data, when
available, at these observing circumstances are inherently advantageous in
constraining thermal inertia and sense of spin, among other physical traits. We
show that, despite the lack of a priori knowledge mentioned above, the size,
albedo, and thermal inertia of an object are well-constrained with precision
comparable to that of previous techniques. Useful estimates of the surface
roughness, shape, and spin direction can also be made, to varying degrees of
success. Applying the method to WISE observations, we present best-fit size,
albedo, thermal inertia, surface roughness, shape elongation and sense of spin
direction for 21 asteroids. We explore the thermal inertia’s correlation with
diameter, after accounting for its dependance on heliocentric distance.
Thermophysical Models (TPMs), which have proven to be a powerful tool in the
interpretation of the infrared emission of asteroid surfaces, typically make
use of a priori obtained shape models and spin axes for use as input boundary
conditions. We test then employ a TPM approach – under an assumption of an
ellipsoidal shape – that exploits the combination of thermal multi-wavelength
observations obtained at pre- and post-opposition. Thermal infrared data, when
available, at these observing circumstances are inherently advantageous in
constraining thermal inertia and sense of spin, among other physical traits. We
show that, despite the lack of a priori knowledge mentioned above, the size,
albedo, and thermal inertia of an object are well-constrained with precision
comparable to that of previous techniques. Useful estimates of the surface
roughness, shape, and spin direction can also be made, to varying degrees of
success. Applying the method to WISE observations, we present best-fit size,
albedo, thermal inertia, surface roughness, shape elongation and sense of spin
direction for 21 asteroids. We explore the thermal inertia’s correlation with
diameter, after accounting for its dependance on heliocentric distance.
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