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Surface evolution in stable magnetic fields: the case of the fully convective dwarf V374 Peg

Published online by Cambridge University Press:  26 August 2011

K. Vida ,
K. Oláh  and
Zs. Kővári
K. Vida
Affiliation:
Konkoly Observatory of the Hungarian Academy of Sciences H-1121 Budapest, Konkoly Thege Miklós str. 15-17. email: vidakris@konkoly.hu
K. Oláh
Affiliation:
Konkoly Observatory of the Hungarian Academy of Sciences H-1121 Budapest, Konkoly Thege Miklós str. 15-17. email: vidakris@konkoly.hu
Zs. Kővári
Affiliation:
Konkoly Observatory of the Hungarian Academy of Sciences H-1121 Budapest, Konkoly Thege Miklós str. 15-17. email: vidakris@konkoly.hu
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Abstract

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We present BV(RI)C photometric measurements of the dM4-type V374 Peg covering ~430 days. The star has a mass of ~0.28MSun, so it is supposed to be fully convective. Previous observations detected almost-rigid-body rotation and stable, axisymmetric poloidal magnetic field. Our photometric data agree well with this picture, one persistent active nest is found on the stellar surface. Nevertheless, the surface is not static: night-to-night variations and frequent flaring are observed. The flares seem to be concentrated on the brighter part of the surface. The short-time changes of the light curve could indicate emerging flux ropes in the same region, resembling to the active nests on the Sun. We have observed flaring and quiet states of V374 Peg changing on monthly timescale.

Keywords

Magnetic fieldstechniques: photometricstars: activitystars: flarestars: individual (V374 Peg)stars: late-typestars: spotsstars: magnetic fields
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 6 , Symposium S273: The Physics of Sun and Star Spots , August 2010 , pp. 460 - 464
Copyright
Copyright © International Astronomical Union 2011

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