Flares in A-type stars?

: Pedersen MG, Antoci V, Korhonen H

: Kosovichev GA, Hawley SL, Heinzel P

: Symposium of the International-Astronomical-Union

: 2016

: Proceedings of the International Astronomical Union

: Solar and stellar flares and their effects on planets

: SOLAR AND STELLAR FLARES AND THEIR EFFECTS ON PLANETS

: IAU SYMP P SERIES

: 11

: S320

: 150

: 152

: 3

: 978-1-10713-757-8

: 1743-9213

DOI: https://doi.org/10.1017/S1743921316002179

Stellar flares are known to originate from magnetic reconnection in the atmospheres of late-type stars or through radiatively driven wind instabilities in early-type stars. Situated right between these two groups, the A-type stars are not expected to support either of the two mechanisms. However, recent studies report flare features in the Kepler light curves of 32 A-type stars, contradicting theory. We investigate the stars reported in literature, setting strong constraints on the detection criteria. Although significantly fewer, we conclude that flare-like features are present. To determine the origin we obtained high-resolution spectra from the Nordic Optical Telescope (NOT) for the ten brightest, flaring A-type stars for 3-4 epochs. Here we present the preliminary results of these spectroscopic observations, with respect to spectral classification and binarity.