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@article{1453618,
author = {Mikulášek, Zdeněk and Krtička, Jiří and Paunzen, Ernst and Švanda, Michal and Hümmerich, Stephan and Bernhard, Klaus and Jagelka, Miroslav and Janík, Jan and Henry, Greg W. and Shultz, Matthew E.},
article_number = {1},
keywords = {stars: chemically peculiar; stars: rotation; stars: individual: sigma Ori E; CU Vir; V901 Ori; and BS Cir; space vehicles: Kepler},
language = {eng},
issn = {1335-1842},
journal = {Contributions of the Astronomical Observatory Skalnaté Pleso},
title = {Differential rotation in magnetic chemically peculiar stars},
volume = {48},
year = {2018}
}
TY - JOUR
ID - 1453618
AU - Mikulášek, Zdeněk - Krtička, Jiří - Paunzen, Ernst - Švanda, Michal - Hümmerich, Stephan - Bernhard, Klaus - Jagelka, Miroslav - Janík, Jan - Henry, Greg W. - Shultz, Matthew E.
PY - 2018
TI - Differential rotation in magnetic chemically peculiar stars
JF - Contributions of the Astronomical Observatory Skalnaté Pleso
VL - 48
IS - 1
SP - 203-207
EP - 203-207
SN - 13351842
KW - stars: chemically peculiar
KW - stars: rotation
KW - stars: individual: sigma Ori E
KW - CU Vir
KW - V901 Ori
KW - and BS Cir
KW - space vehicles: Kepler
N2 - Magnetic chemically peculiar (mCP) stars constitute about 10% of upper-main-sequence stars and are characterized by strong magnetic fields and abnormal photospheric abundances of some chemical elements. Most of them exhibit strictly periodic light, magnetic, radio, and spectral variations that can be fully explained by a rigidly rotating main-sequence star with persistent surface structures and a stable global magnetic field. Long-term observations of the phase curves of these variations enable us to investigate possible surface differential rotation with unprecedented accuracy and reliability. The analysis of the phase curves in the best-observed mCP stars indicates that the location and the contrast of photometric and spectroscopic spots as well as the geometry of the magnetic field remain constant for at least many decades. The strict periodicity of mCP variables supports the concept that the outer layers of upper-main-sequence stars do not rotate differentially. However, there is a small, inhomogeneous group consisting of a few mCP stars whose rotation periods vary on timescales of decades. The period oscillations may reflect real changes in the angular velocity of outer layers of the stars which are anchored by their global magnetic fields. In CU Vir, V901 Ori, and perhaps BS Cir, the rotational period variation indicates the presence of vertical differential rotation; however, its exact nature has remained elusive until now. The incidence of mCP stars with variable rotational periods is currently investigated using a sample of fifty newly identified Kepler mCP stars.
ER -
MIKULÁŠEK, Zdeněk, Jiří KRTIČKA, Ernst PAUNZEN, Michal ŠVANDA, Stephan HÜMMERICH, Klaus BERNHARD, Miroslav JAGELKA, Jan JANÍK, Greg W. HENRY a Matthew E. SHULTZ. Differential rotation in magnetic chemically peculiar stars. \textit{Contributions of the Astronomical Observatory Skalnaté Pleso}. 2018, roč.~48, č.~1, s.~203-207. ISSN~1335-1842.
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