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

SYSNO ASEP	0479263
Document Type	J - Journal Article
R&D Document Type	Journal Article
Subsidiary J	Článek ve WOS
Title	Torsional oscillations and observed rotational period variations in early-type stars
Author(s)	Krtička, J. (CZ) Mikulášek, Z. (CZ) Henry, G.W. (US) Kurfürst, P. (CZ) Karlický, Marian (ASU-R)_{RID, ORCID}
Source Title	Monthly Notices of the Royal Astronomical Society. - : Oxford University Press - ISSN 0035-8711 Roč. 464, č. 1 (2017), s. 933-939
Number of pages	7 s.
Publication form	Print - P
Language	eng - English
Country	GB - United Kingdom
Keywords	MHD ; chemically peculiar stars ; early-type stars
Subject RIV	BN - Astronomy, Celestial Mechanics, Astrophysics
OECD category	Astronomy (including astrophysics,space science)
R&D Projects	GA16-01116S GA ČR - Czech Science Foundation (CSF)
	GAP209/12/0103 GA ČR - Czech Science Foundation (CSF)
Institutional support	ASU-R - RVO:67985815
UT WOS	000393646300070
EID SCOPUS	85014762391
DOI	10.1093/mnras/stw2451
Annotation	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.
Workplace	Astronomical Institute
Contact	Radka Svašková, bibl@asu.cas.cz, Tel.: 323 620 326
Year of Publishing	2018

Number of the records: 1