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V2487 Oph is a recurrent nova with detected eruptions in 1900 and 1998.Startlingly, V2487 Oph shows flares, called `Superflares', with up to 1.10 magamplitude, fast rises of under one-minute, always with an initial impulsivespike followed by a roughly-exponential tail, typically one-hour durations, andwith random event times averaging once-per-day. The typical flare energy $E$ isover 10$^{38}$ ergs, while the yearly energy budget is 10$^{41}$ ergs. V2487Oph Superflares obey three relations; the number distribution of flare energiesscales as $E^{-2.34\pm0.35}$, the waiting time from one flare to the next isproportional to $E$ of the first event, and flare durations scale as$E^{0.44\pm0.03}$. Scenarios involving gravitational energy and nuclear energyfail to satisfy the three relations. The magnetic energy scenario, however, canexplain all three relations. This scenario has magnetic field lines above thedisc being twisted and amplified by the motions of their footprints, withmagnetic reconnection releasing energy that comes out as Superflare light. Thisexact mechanism is already well known to occur in white light solar flares, inordinary M-type flare stars, and in the many Superflare stars observed allacross the H-R diagram. Superflares on Superflare stars have rise times, lightcurve shapes and durations that are very similar to those on V2487 Oph. So weconclude that the V2487 Oph Superflares are caused by large-scale magneticreconnection. V2487 Oph is now the most extreme Superflare star, exhibiting thelargest known flare energy (1.6$\times$10$^{39}$ ergs) and the fastestoccurrence rate.

Discovery of Extreme, Roughly-Daily Superflares on the Recurrent Nova V2487 Oph