Establish whether irradiation can produce specularly reflective asteroid surfaces

Establish whether ion or electron irradiation in the outer Van Allen belt can smooth asteroid or metallic-fragment surfaces sufficiently to enhance their specular optical reflectivity under realistic material compositions and irradiation conditions.

Background

The paper considers whether small natural bodies or asteroid fragments with planar metallic or icy surfaces could generate the observed short-duration flashes. It notes that irradiation by charged particles might, in some circumstances, remove softer materials and smooth surface irregularities at nano- to micro-scales, potentially producing stronger specular reflection.

The authors do not establish that this mechanism occurs or that it is effective in the relevant orbital environment. Its feasibility depends on the composition of the material and the intensity and duration of irradiation, leaving the proposed natural explanation unresolved.

References

However, it has been suggested that ion or electron irradiation could in some cases act analogously to beam polishing, preferentially removing softer materials and smoothing surface irregularities at nano- to micro-scales, potentially enhancing specular reflectivity. This remains speculative and depends sensitively on the material composition and irradiation conditions.

— Modelling Palomar Transients: Constraints from Reflection Geometry and Orbital Altitude  (2609.05105 - Villarroel et al., 4 Sep 2026) in Section 5.2.1, “Natural bodies?”