Spectroscopic Measurements for Possible Cometary Dust Analogues

We present new spectroscopic measurements for two dust analogue samples: walnut charcoal and willow charcoal. These measurements were performed in our laboratory using a Cary 5000 spectrometer equipped with an integrating sphere. This measurement setup enabled the measurement of hemispherical albedo as a function of wavelength in the range from 200 to 2500 nm. The obtained hemispherical albedo values ranged from 0.10 to 10.89%. Based on the obtained spectral profile measurements, the Bond albedo and geometric albedo values were calculated for selected possible analogues of refractory material present on cometary surfaces. The obtained mean Bond albedo value was 0.49%, while the mean geometric albedo value was 1.90%. These results were compared with macromolecular carbonaceous material present in cometary dust from comets. The obtained results were compared with measurements made by Rosetta/COSIMA, which showed that the cometary dust is dominated by macromolecular carbonaceous material, which is responsible for the very low albedo of comet 67P/Churyumov–Gerasimenko. Abstract Published by the Jagiellonian University 2026 authors