A4 Refereed article in a conference publication
Flares in A-type stars?
Authors: Pedersen MG, Antoci V, Korhonen H
Editors: Kosovichev GA, Hawley SL, Heinzel P
Conference name: Symposium of the International-Astronomical-Union
Publication year: 2016
Journal: Proceedings of the International Astronomical Union
Book title : Solar and stellar flares and their effects on planets
Journal name in source: SOLAR AND STELLAR FLARES AND THEIR EFFECTS ON PLANETS
Journal acronym: IAU SYMP P SERIES
Volume: 11
Issue: S320
First page : 150
Last page: 152
Number of pages: 3
ISBN: 978-1-10713-757-8
ISSN: 1743-9213
DOI: https://doi.org/10.1017/S1743921316002179(external)
Abstract
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.
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.
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