TESS flare statistics and debiasing. The top horizontal axis of each subpanel indicates the nominal stellar spectral types (Pecaut & Mamajek 2013). (a) Average TESS ensemble flare rate, defined as the fraction of flaring stars N_flaring/N_total in the TESS short-cadence years 1 and 2 observations, weighted by the average flare rate v_TESS, as a function of stellar effective temperature T_eff. v_TESS follows the definition from Eq. (2). The green curve shows the average TESS ensemble flare rate using the entire TESS flare statistics which suffers greatly from TESS sampling bias (see Sect. 3.3.1), whereas the orange curve only considers TESS stars within 50pc, with the blue curve as its polynomial fit (from numpy.polyfit; deg = 5) used for subsequent analysis. M dwarfs later than ~M6 were not observed in a large enough sample size due to TESS target selection (which avoids very faint stars), and are thus excluded (represented by the red region). (b) Stellar radius R, as a function of T_eff. The Basti-IAC isochrone model (Hidalgo et al. 2018) and the BHAC15 isochrone model (Baraffe et al. 2015) are combined to create our interpolated model. (c) Minimum flare energy E_f,min detectable by TESS on a particular star with effective temperature T_eff. The unit for the flare energy is arbitrary since we are only interested in the shape of the E_f,min vs. spectral type curve. (d) Same as Fig. 1a, but with the debiased flare rate v instead of the TESS-observed flare rate v_TESS. This debiased average-TESS-ensemble-flare-rate curve is obtained by multiplying the two blue curves in Figs. 1a and c.