arXiv 1606.093242016-06-30astro-ph.SR

盾牌座$δ$星HD 50844的星震学

Asteroseismology of the $δ$ Scuti star HD 50844

X. H. Chen, Y. Li, X. J. Lai, T. Wu

备注：: 11 pages, 7 figures, 6 tables, accepted for publication in A&A
发表信息：: A&A 593, A69 (2016)
DOI：: 10.1051/0004-6361/201628197

摘要：

目的。我们的目标是探测$δ$ Scuti星HD 50844的内部结构，并研究更详细的信息。方法.我们分析了Balona（2014）获得的$δ$ Scuti星HD 50844的观测频率，并根据g模的旋转分裂定律寻找可能的多重态。我们试图通过旋转分裂的方式解开HD 50844的频谱。然后，我们将它们与理论脉动模式进行比较，这些模式对应于具有各种初始金属丰度和恒星质量的恒星演化模型，以找到最佳拟合模型。结果三重态包括两个完全三重态和一个不完全五重态，其中球谐次数$l$和方位角数$m$的模式识别是唯一的。HD 50844的相应自转周期为2.44 $^{+0.13}_{-0.08}$天。HD 50844的物理参数在一个小区域内受到三种非径向模式（$f_{11}$、$f_{22}$和$f_{29}$）和基本径向模式（$f_{4}$）的限制。结果表明，三种非径向模（$f_{11}$，$f_{22}$，和$f_{29}$）都是混合模，主要代表氦核的性质.基本径向模（$f_{4}$）主要代表恒星包层的性质。为了符合这四种脉动模式，氦核和恒星外壳都必须与HD 50844的实际结构相匹配。最后，HD 50844的氦核质量首次被估计为0.173 $\pm$ 0.004 $M_{\odot}$。HD 50844的物理参数确定为$M=$ 1.81 $\pm$ 0.01 $M_{\odot}$、$Z=$ 0.008 $\pm$ 0.001。$T_{\rm eff}=$ 7508 $\pm$ 125 K，log $g=$ 3.658 $\pm$ 0.004，$R=$ 3.300 $\pm$ 0.023 $R_{\odot}$，$L=$ 30.98 $\pm$ 2.39 $L_{\odot}$。

英文摘要：

Aims. We aim to probe the internal structure and investigate more detailed information of the $δ$ Scuti star HD 50844 with asteroseismology. Methods. We analyse the observed frequencies of the $δ$ Scuti star HD 50844 obtained by Balona (2014), and search for possible multiplets based on the rotational splitting law of g-mode. We tried to disentangle the frequency spectra of HD 50844 by means of the rotational splitting only. We then compare them with theoretical pulsation modes, which correspond to stellar evolutionary models with various sets of initial metallicity and stellar mass, to find the best-fitting model. Results. There are three multiplets including two complete triplets and one incomplete quintuplet, in which mode identifications for spherical harmonic degree $l$ and azimuthal number $m$ are unique. The corresponding rotational period of HD 50844 is found to be 2.44$^{+0.13}_{-0.08}$ days. The physical parameters of HD 50844 are well limited in a small region by three modes identified as nonradial ones ($f_{11}$, $f_{22}$, and $f_{29}$) and by the fundamental radial mode ($f_{4}$). Our results show that the three nonradial modes ($f_{11}$, $f_{22}$, and $f_{29}$) are all mixed modes, which mainly represent the property of the helium core. The fundamental radial mode ($f_{4}$) mainly represents the property of the stellar envelope. In order to fit these four pulsation modes, both the helium core and the stellar envelope must be matched to the actual structure of HD 50844. Finally, the mass of the helium core of HD 50844 is estimated to be 0.173 $\pm$ 0.004 $M_{\odot}$ for the first time. The physical parameters of HD 50844 are determined to be $M=$ 1.81 $\pm$ 0.01 $M_{\odot}$, $Z=$ 0.008 $\pm$ 0.001. $T_{\rm eff}=$ 7508 $\pm$ 125 K, log$g=$ 3.658 $\pm$ 0.004, $R=$ 3.300 $\pm$ 0.023 $R_{\odot}$, $L=$ 30.98 $\pm$ 2.39 $L_{\odot}$.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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