Pushing the Limits of High-Cadence Stellar Photometry: Flare Variability at 2.7 s with CHEOPS

Characterising the shortest timescales of energy release in stellar flares is essential for understanding the corona and stellar activity in general. We are interested in quasi-periodic pulsations (QPPs) which are frequently observed in Solar flares with periods ranging from a few seconds to several minutes. Observations of stellar flares from space-photometry have reported QPPs with a periodicity down to 40s. However, the presence of short-period QPPs in the optical regime is often masked by stochastic noise and their detection suffer from insufficient temporal resolution. Here, we present new observations with the ESA space mission CHEOPS to investigate the high-frequency behaviour of flares on active cool stars. The unprecedented temporal resolution of 2.7s allows us to probe a temporal regime that is typically inaccessible with standard space-based photometry. We characterise the short-term variability of our Solar-like targets and present our search for short-period oscillations during flaring events. This work highlights the potential of the CHEOPS mission for short cadence observations of stellar variability.