Long-term monitoring of comet 29P/Schwassmann–Wachmann from the Lulin Observatory.

This article focuses on multi-band photometric monitoring of comet 29P/Schwassmann–Wachmann 1 (P/SW 1) from July 2018 to December 2021, documenting at least 12 significant outbursts characterized by brightness increases of 1.5 to 5 magnitudes. A unique quadruple outburst in late September 2021 showed continuous activity over several days, accompanied by changes in coma morphology, brightness profiles, and a slight bluing in color indices (notably B − V), likely due to dust fragmentation. The study estimated dust expansion velocities around 0.11 km/s and dust production rates rising from tens to thousands of kilograms per second during outbursts, with total ejected dust mass increasing by two orders of magnitude compared to quiescent levels. These findings contribute to understanding the comet’s unusual frequent outbursts driven primarily by carbon monoxide sublimation at large heliocentric distances and highlight challenges in determining its rotational period.