Temporal–Chromatic Coherence in Rubin/LSST Light Curves as a Pathfinder for Small-Body Missions

The Vera C. Rubin Observatory Legacy Survey of Space and Time  (LSST) will provide multiband time-domain photometry for large Solar System populations. We present a Rubin-like simulation framework in which synthetic multiband light curves are analysed under irregular LSST cadence using cross-band correlation, same-night coherence, colour scatter, amplitude stability, and phase stability. The simulated coherent class includes stable cross-band modulation on tens-of-days timescales, best interpreted as slowly evolving activity, dust/coma evolution, or observing-geometry effects rather than rapid rotational light curves.

Applied to 500 synthetic Rubin-like light curves, the framework separates coherent, natural stochastic, and noise-dominated variability into distinct regions of temporal–chromatic coherence space. This provides a survey-to-mission filtering layer for identifying weakly active, volatile-rich, or transitional small bodies whose organized multiband behaviour makes them promising candidates for spectroscopic follow-up and future spacecraft characterization. Rubin/LSST coherence diagnostics can therefore bridge large-scale discovery, physical interpretation, and mission-target prioritization.