Possible analogues of cometary refractory material: geometric albedo and Bond albedo

In this paper, we present the results of hemispherical albedo measurements for selected analogs (various types of charcoal and soot) of refractory materials present in cometary dust. Based on the obtained spectral profiles, we estimated the Bond albedo, geometric albedo, and spectral slopes. The calculated Bond albedo ranges from 0.36% to 1.20%, while the geometric albedo ranges from 1.43% to 4.74%, assuming a phase integral of q = 0.253. The obtained results were compared with macromolecular carbonaceous material present in cometary dust from comets. Comparative analysis indicates that not all types of charcoal and soot are suitable analogues of refractory material in cometary dust. Considering the geometric albedo and the influence of grain diameter in the tested samples, the most suitable materials among the studied charcoals and soots are pine wood charcoal and commercial soot, respectively. Comparison of the laboratory results with observational data demonstrates the importance of laboratory measurements in the interpretation of astronomical observations. They enable the calibration of photometric models and reduce interpretative uncertainties. Therefore, laboratory experiments constitute an essential component in the interpretation of the photometric properties of comet nuclei.