KIC 2852961 -- a superflaring red monster in the Kepler field

TL;DR

This paper studies superflares on the giant star KIC 2852961 using Kepler data, finding that its flare energy distribution differs from solar-type superflares and suggesting star spots play a key role.

Contribution

It provides the first detailed analysis of superflares on a giant star, challenging the solar dynamo scaling hypothesis and highlighting the importance of star spots.

Findings

Flare energy distribution differs from solar-type superflares.

Spot activity likely influences superflares on KIC 2852961.

Superflares on giant stars may have different mechanisms than on solar-type stars.

Abstract

Superflares on giant stars have up to 100,000 times more energy than the high energy solar flares. However, it is disputed, whether scaling up a solar-type dynamo could explain such a magnitude difference. We investigate the flaring activity of KIC 2852961, a late-type spotted giant. We seek for flares in the Kepler Q0-Q17 datasets by an automated technique together with visual inspection. Flare occurence rate and flare energies are analyzed and compared to flare statistics of different targets with similar flare activity at different energy levels. We find that the flare energy distribution of KIC 2852961 does not seem to be consistent with that of superflares on solar-type stars. Also, we believe that in case of KIC 2852961 spot activity should have an important role in producing such superflares.