Flare detections of TOI host stars

We perform the first flare survey of all 2250 non-retired TOIs with 2-min cadence light curves to measure or place upper limits on their flare rates. We find 93 candidates orbit flare stars and measure their flare frequency distributions.

Across the sample, TOIs of <= 1.5R_{Earth}_ orbit flare stars more frequently than do TOIs of 1.5 < R < 2.75R_{Earth}_, 2.75 < R< 4R_{Earth}_, or R => 4R_{Earth}_. We sort all TOI host stars by their flare rate/upper limit, stellar mass, and distance to create a flare ranking metric (FRM) to determine suitability for follow-up. The FRM of each TOI is then checked against the expected signal-to-noise of atmospheric features in transmission spectroscopy to locate the most promising targets.