Multi-wavelength phase curves of asteroids

The arrival of extensive multi-wavelength photometric surveys opens a window into exploring aspects of astrophysics in ways that were not possible before. In particular, studying scores of small bodies observed serendipitously at different orbital locations in different epochs allows us to understand the phase-angle
dependence of their photometric properties while obtaining their absolute magnitudes.

In this work, I present recent results showing that the surfaces of small bodies do not follow a unique color trend with phase angle (the so-called "phase reddening") but instead have a dual behavior with a change at a critical angle of about α = 5 deg. On the other hand, the large number of results opens for a critical revision of long-standing relations involving phase coefficients and observables, such as taxa and albedo, which may not hold.

The main results of this work can be summarized as follows: (1) Using observations at a single epoch may bias the results, (2) long-used observational relations may not survive the increase in the number of data, and (3) small bodies' reflectance properties do not behave as suspected.