# TESS Program G06108

Title: Magnetic Activity On Rapidly-Rotating Red Giants With 200-Second TESS Ffis

PI: Ong, Joel - University Of Hawaii (Manoa)

Type: SMALL

Summary: Red giants are expected not to exhibit any significant surface rotation, but some rapidly-rotating red giants (RRRGs) do. Their photometric modulations also suggest surface features of magnetic origin, through a convective dynamo driven precisely by this anomalous rotation. Photometric transients associated with flares, which should in principle also result from this dynamo action, had been observationally inaccessible owing to temporal undersampling at 30-minute cadence, save for a very select few red giants previously targeted at short cadence. The new availability of 200 second full-frame images (FFIs) now permits TESS to probe time-domain magnetic activity of essentially all visible RRRGs in a hitherto observationally inaccessible temporal regime. We propose to study this activity.