Informace o publikaci

Torsional oscillations and observed rotational period variations in early-type stars

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KRTIČKA Jiří MIKULÁŠEK Zdeněk HENRY Gregory W. KURFÜRST Petr KARLICKY Marian

Rok publikování 2017
Druh Článek v odborném periodiku
Časopis / Zdroj Monthly Notices of the Royal Astronomical Society
Fakulta / Pracoviště MU

Přírodovědecká fakulta

Citace
www http://adsabs.harvard.edu/abs/2017MNRAS.464..933K
Doi http://dx.doi.org/10.1093/mnras/stw2451
Obor Astronomie a nebeská mechanika, astrofyzika
Klíčová slova MHD stars; chemically peculiar stars; early-type stars; magnetic field; stars rotation
Popis Some chemically peculiar stars in the upper main sequence show rotational period variations of unknown origin. We propose that these variations are a consequence of the propagation of internal waves in magnetic rotating stars that lead to the torsional oscillations of the star. We simulate the magnetohydrodynamic waves and calculate resonant frequencies for two stars that show rotational variations: CU Vir and HD 37776. We provide updated analyses of rotational period variations in these stars and compare our results with numerical models. For CU Vir, the length of the observed rotational period cycle, Pi=67.6(5) yr, can be well reproduced by the models, which predict a cycle length of 51 yr. However, for HD 37776, the observed lower limit of the cycle length, Pi>100 yr, is significantly longer than the numerical models predict. We conclude that torsional oscillations provide a reasonable explanation at least for the observed period variations in CU Vir.
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