Indhu Varatharajan

and 7 more

Specialized spectral library measured under controlled planetary surface conditions is important to accurately derive the chemical and physical properties from remote observations. It’s a general practice to powder the planetary analogues during spectroscopy studies as most surfaces are made up of fine-regolith materials. However, upon arrival at C-type asteroids Ryugu and Bennu, Hayabusa2 and OSIRIS-REx revealed these surfaces filled with rocks and boulders. In this study, we built a phase angle dependent ultraviolet (UV) to far-infrared (FIR) spectroscopy (0.2-100 µm) of a rocky piece of Mukundpura meteorite having five surfaces including fusion crust. Mukundpura meteorite is the freshest carbonaceous chondrite belonging to CM-chondrites in the entire collection which fell in the desert village of India on June 6, 2017. The two sets of varying viewing geometries having incident and reflectance angles includes ; a) asymmetric viewing geometry at 13°-13°, 13°-20°, 13°-30°, 13°-40°, and 13°-50°, and b) symmetric viewing geometry at 13°-13°, 20°-20°, 30°-30°, 40°-40°, and 50°-50°. This study found that overall spectral shape, reflectance values, and band depth of diagnostic absorption features are affected by viewing geometry and surface roughness; however, the fundamental band centers are not affected. The comparison of 2.72 µm absorption band of fusion crust and fresh interiors of Mukundpura with published Ryugu and Bennu spectra supports that Ryugu surface has experienced extensive heating in its geologic past compared to Bennu. Overall study shows that fusion crust and internal surfaces of the Mukundpura meteorite is a potential analogue of Ryugu and Bennu both spectrally and morphologically.