Asteroid shapes and thermal properties from combined optical and mid-infrared photometry inversion

Abstract

Optical lightcurves can be used for the shape and spin reconstruction of asteroids. Due to unknown albedo, these models are scale-free. When thermal infrared data are available, they can be used for scaling the shape models and for deriving thermophysical properties of the surface by applying a thermophysical model. We introduce a new method of simultaneous inversion of optical and thermal infrared data that allows the size of an asteroid to be derived along with its shape and spin state. The method optimizes all relevant parameters (shape and its size, spin state, light-scattering properties, thermal inertia, surface roughness) by gradient-based optimization. The thermal emission is computed by solving the 1-D heat diffusion equation. Calibrated optical photometry and thermal fluxes at different wavelengths are needed as input data. We demonstrate the reliability and test the accuracy of the method on selected targets with different amount and quality of data. Our results in general agree with those obtained by independent methods. Combining optical and thermal data into one inversion method opens a new possibility for processing photometry from large optical sky surveys with the data from WISE. It also provides more realistic estimates of errors of thermophysical parameters.

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Cited by in corpus (12)

• Thermophysical modeling of main-belt asteroids from WISE thermal data
• SsODNet: The Solar system Open Database Network
• Asteroid models reconstructed from the Lowell Photometric Database and WISE data
• Thermal properties of slowly rotating asteroids: Results from a targeted survey
• Small Bodies: Near and Far Database for thermal infrared observations of small bodies in the Solar System
• Thermal properties of large main-belt asteroids observed by Herschel PACS
• $V$-band photometry of asteroids from ASAS-SN: Finding asteroids with slow spin
• Properties of slowly rotating asteroids from the Convex Inversion Thermophysical Model
• Volume uncertainty assessment method of asteroid models from disk-integrated visual photometry
• Thermophysical Modeling of Asteroid Surfaces using Ellipsoid Shape Models
• (208) Lacrimosa: A case that missed the Slivan state?
• Asteroid sizes determined with thermophysical model and stellar occultations