Impact of Porosity on Spectro-Photometric Properties of Phobos Simulants
Recent research has focused on the spectro-photometric properties of Phobos simulants, specifically examining how porosity affects these characteristics. The study, titled "Spectro-photometry of Phobos simulants: II. Effects of porosity," was conducted by Antonin Wargnier and a team of researchers and submitted to the journal Icarus on August 26, 2024.
The investigation revealed that surface porosity is a significant property for small celestial bodies, such as asteroids and comets. The researchers created simulants of Phobos regolith by mixing them with ultra-pure water, which produced ice-dust particles that were later sublimated. This process allowed for a detailed analysis of the reflectance spectroscopic properties in the visible and near-infrared ranges (0.5-4.2 μm).
Findings indicated that there were no strong variations in reflectance between porous and compact samples, although one simulant displayed a bluing of the slope with increased porosity. This observation may provide insights into the differences between the blue and red units observed on Phobos. Additionally, in the mid-infrared range, an increase in the contrast of the 10-μm emissivity plateau due to silicates was noted.
The study also reported modifications in phase reddening behavior between compact powder and sublimation residue for both simulants, suggesting that the phase reddening may depend on the simulants' composition. The addition of porosity appeared to enhance forward scattering in the phase curve, indicating increased roughness in the porous samples without significantly altering the opposition effect.
These insights are particularly relevant in the context of the upcoming JAXA/Martian Moons eXploration mission, as they contribute to a better understanding of the physical properties of Phobos and similar celestial bodies. The research underscores the importance of porosity in interpreting the spectro-photometric data of small bodies in our solar system, which could have implications for future exploration and study of these distant worlds.
For further details, the full paper can be accessed here.