Program: GS-2024A-Q-111

We request Gemini observing time to obtain monitoring observations using GMOS-N and GMOS-S to study the activity evolution of main-belt comets (MBCs) 133P, 358P, 426P, and 457P, all of which are expected to be active in 2024A, where 133P and 358P are also the targets of JWST Cycle 2 observations. JWST recently detected water outgassing in a MBC for the first time in Cycle 1 (which had not been possible until then from ground-based facilities), and will observe two more MBCs in Cycle 2. Contemporaneous JWST and ground-based observations of MBCs enable researchers to determine typical dust-to-water production rate ratios, and then use that information to estimate water production rates from the much larger set of available ground-based observations of MBCs. Our proposed observations will help to extend the impact of limited JWST observations to a much larger population of objects than would be possible to study with JWST alone, and will also contribute to efforts to characterize long-term MBC activity evolution.