Spectroscopic, photometric, and polarimetric modeling of asteroid (4) Vesta
Abstract
We present a novel simulation framework for modeling the spectroscopy, photometry, and polarimetry of asteroid (4) Vesta. The data provided by the Dawn mission suggest that the mineral composition of Vesta's surface regolith is similar to howardites, achondritic stony meteorites that together with eucrites and diogenites represent the HED meteorite clan. We derive the complex refractive indices of howardite powder at a wavelength region of 0.4 to 2.5 μm. The modeling is carried out in multiple parts: first, we use the volume-integral-equation method (e.g. [Markkanen et al. 2015, Planetary and Space Science 118]) to compute light-scattering properties of wavelength-scale howardite particles. Second, we utilize SIRIS4 [Lindqvist et al. 2018, JQSRT],[Martikainen et al. 2018, JQSRT 204], a ray-optics code that simulates light scattering by Gaussian-random-sphere particles, to account for howardite particles that are larger than the wavelength of the incident light. Finally, we combine the small and the large particles by using a power-law size distribution. With a single model, we aim to obtain the particle size distribution and mineral composition of Vesta's surface regolith, and to explain the observed opposition effect and negative linear polarization.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.P33D3865M
- Keywords:
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- 6024 Interiors;
- PLANETARY SCIENCES: COMETS AND SMALL BODIESDE: 6055 Surfaces;
- PLANETARY SCIENCES: COMETS AND SMALL BODIESDE: 6063 Volcanism;
- PLANETARY SCIENCES: COMETS AND SMALL BODIESDE: 6205 Asteroids;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS