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Flares in A-type stars?

Published online by Cambridge University Press:  09 September 2016

May G. Pedersen
Affiliation:
Stellar Astrophysics Centre (SAC), Aarhus University, Nordre Ringgade 1, DK-8000 Aarhus C, Denmark, email: maygp@phys.au.dk & antoci@phys.au.dk
Victoria Antoci
Affiliation:
Stellar Astrophysics Centre (SAC), Aarhus University, Nordre Ringgade 1, DK-8000 Aarhus C, Denmark, email: maygp@phys.au.dk & antoci@phys.au.dk
Heidi Korhonen
Affiliation:
Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, FI-21500 Piikkiö, Finland email: heidi.h.korhonen@utu.fi
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Abstract

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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.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2016 

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