Title: Frequent flaring in the TRAPPIST-1 system - unsuited for life?,
Abstract: We analyze short cadence K2 light curve of the TRAPPIST-1 system. Fourier
analysis of the data suggests $P_\mathrm{rot}=3.295\pm0.003$ days. The light
curve shows several flares, of which we analyzed 42 events, these have
integrated flare energies of $1.26\times10^{30}-1.24\times10^{33}$ ergs.
Approximately 12% of the flares were complex, multi-peaked eruptions. The
flaring and the possible rotational modulation shows no obvious correlation.
The flaring activity of TRAPPIST-1 probably continuously alters the atmospheres
of the orbiting exoplanets, making these less favorable for hosting life.