Component periods of non-principal-axis rotation and their manifestations in the lightcurves of asteroids and bare cometary nuclei

Abstract

Lightcurve observations of asteroids and bare cometary nuclei are the most widely used observational tool to derive the rotational parameters. Therefore, an in-depth understanding of how component periods of dynamically excited non-principal axis (NPA) rotators manifest in lightcurves is a crucial step in this process. We investigated this with the help of numerically generated lightcurves of NPA rotators with component periods known a priori. The component periods of NPA rotation were defined in terms of two widely used yet complementary conventions. We derive the relationships correlating the component rotation periods in the two conventions. These relationships were then used to interpret the periodicity signatures present in the simulated lightcurves and rationalize them in either convention.