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标题：Constraining the near-core rotation of the γ Doradus star 43 Cygni using BRITE-Constellation data
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作者：K. Zwintz ; T. Van Reeth ; A. Tkachenko 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2017
卷号：608
页码：1-9
DOI：10.1051/0004-6361/201731784
语种：English
出版社：EDP Sciences
摘要：Context.Photometric time series of theγDoradus star 43 Cyg obtained with the BRITE-Constellation nano-satellites allow us to study its pulsational properties in detail and to constrain its interior structure.Aims.We aim to find ag-mode period-spacing pattern that allows us to determine the near-core rotation rate of 43 Cyg and redetermine the star’s fundamental atmospheric parameters and chemical composition.Methods.We conducted a frequency analysis using the 156-day long data set obtained with the BRITE-Toronto satellite and employed a suite of MESA/GYRE models to derive the mode identification, asymptotic period-spacing, and near-core rotation rate. We also used high-resolution spectroscopic data with high signal-to-noise ratio obtained at the 1.2 m Mercator telescope with the HERMES spectrograph to redetermine the fundamental atmospheric parameters and chemical composition of 43 Cyg using the software Spectroscopy Made Easy (SME).Results.We detected 43 intrinsic pulsation frequencies and identified 18 of them to be part of a period-spacing pattern consisting of prograde dipole modes with an asymptotic period-spacingΔΠl= 1of 2970-570+700 s. The near-core rotation rate was determined to befrot= 0.56-0.14+0.12d-1. The atmosphere of 43 Cyg shows solar chemical composition at an effective temperature,Teff, of 7150±150 K, alog gof 4.2±0.6 dex, and a projected rotational velocity,υsini, of 44±4 km s-1.Conclusions.The morphology of the observed period-spacing patterns shows indications of a significant chemical gradient in the stellar interior.
关键词：enasteroseismologystars: individual: 43 Cygnistars: interiorsstars: oscillationsstars: fundamental parameters