An Efficient and Lightweight Illumination Model for Planetary Bodies Including Direct and Diffuse Radiation

Area of Science:

• Planetary Science
• Astrophysics
• Computational Modeling

Background:

• Accurate simulation of solar radiation on planetary surfaces is crucial for understanding celestial body illumination.
• Existing models often have limitations regarding surface complexity and scattering phenomena.

Purpose of the Study:

• To develop a versatile numerical illumination model for arbitrary planetary surfaces.
• To incorporate direct and diffuse (Hapke) scattered radiation, including mutual and self-illumination.
• To validate the model's accuracy using real-world observational data.

Main Methods:

• Utilized the ray tracing method for robust geometric calculations.
• Incorporated digital terrain data of arbitrary spatial resolution.
• Accounted for wavelength-dependent effects like albedo and implemented mutual/self-illumination.

Main Results:

• The model successfully simulates direct and diffuse radiation scenarios on complex surfaces.
• Demonstrated capability to handle arbitrary shapes beyond spheres and ellipsoids.
• Validated against DAWN mission survey phase images of asteroid 4 Vesta using a chi-squared test.

Conclusions:

• The developed numerical illumination model is a valid and versatile tool for planetary surface studies.
• The model's ability to handle complex terrains and illumination scenarios enhances remote sensing and mission planning.
• Future applications include detailed analysis of small bodies and cratered surfaces.