Kepler super-flare stars: what are they?

The Kepler mission has led to the serendipitous discovery of a significant number of super flares - white light flares with energies between 10(33) erg and 10(36) erg - on solar-type stars. It has been speculated that these could be freak events that might happen on the Sun, too. We have started a programme to study the nature of the stars on which these super flares have been observed. Here we present high-resolution spectroscopy of 11 of these stars and discuss our results. We find that several of these stars are very young, fast-rotating stars where high levels of stellar activity can be expected, but for some other stars we do not find a straightforward explanation for the occurrence of super flares.