arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1010.2146astro-ph.SR
收藏

用VEGA/CHARA干涉仪研究β Cep的封闭环境

An investigation of the close environment of beta Cep with the VEGA/CHARA interferometer

N. Nardetto, D. Mourard, I. Tallon-Bosc, M. Tallon, P. Berio, E. Chapellier, D. Bonneau, O. Chesneau, P. Mathias, K. Perraut, P. Stee, A. Blazit, J. M. Clausse,… 展开作者

N. Nardetto, D. Mourard, I. Tallon-Bosc, M. Tallon, P. Berio, E. Chapellier, D. Bonneau, O. Chesneau, P. Mathias, K. Perraut, P. Stee, A. Blazit, J. M. Clausse, O. Delaa, A. Marcotto, F. Millour, A. Roussel, A. Spang, H. McAlister, T. ten Brummelaar, J. Sturmann, L. Sturmann, N. Turner, C. Farrington, P. J. Goldfinger

摘要:

对脉动恒星进行高精度干涉测量有助于确定其近距离环境的特征。在1974年,一个近伴星被发现围绕脉动星β Cep使用散斑干涉测量技术和功能的极限分辨率(20毫弧秒或mas)的仪器提到,可能是由于拱星材料。Cep β有一个磁场,这可能是MHD模型所描述的围绕恒星的球壳或环状结构的原因。利用安装在Mt. CHARA长基线干涉仪上的可见光复合器VEGA。Wilson,我们的目标是确定β Cep的角直径,并以高达1 mas水平的空间分辨率解决其封闭环境。在2008年和2009年期间,VEGA仪器获得了β Cep的中等光谱分辨率(R=6000)观测。这些观测是用阵列的S1 S2(30米)和W1 W2(100米)基线进行的。我们研究了几个模型来重现我们的观察结果。一个大尺度结构的几个质量是清楚地检测到周围的恒星与一个典型的通量相对贡献为0.23 +- 0.02。我们最好的模型是一个共同旋转的几何薄环周围的恒星预测的磁约束风冲击模型。环内径为8.2 ± 0.8质量,宽度为0.6 ± 0.7质量。旋转轴在天空平面上的方向是PA = 60 +- 1 deg,而β Cep的平均角直径的最佳拟合给出UD[V] = 0.22 +- 0.05 mas。我们的数据与预测的β Cep近伴星的位置一致。这些结果带来了额外的限制的基本参数和未来的MHD和asteroseisological模型的明星。

英文摘要:

High-precision interferometric measurements of pulsating stars help to characterize their close environment. In 1974, a close companion was discovered around the pulsating star beta Cep using the speckle interferometry technique and features at the limit of resolution (20 milli-arcsecond or mas) of the instrument were mentioned that may be due to circumstellar material. Beta Cep has a magnetic field that might be responsible for a spherical shell or ring-like structure around the star as described by the MHD models. Using the visible recombiner VEGA installed on the CHARA long-baseline interferometer at Mt. Wilson, we aim to determine the angular diameter of beta Cep and resolve its close environment with a spatial resolution up to 1 mas level. Medium spectral resolution (R=6000) observations of beta Cep were secured with the VEGA instrument over the years 2008 and 2009. These observations were performed with the S1S2 (30m) and W1W2 (100m) baselines of the array. We investigated several models to reproduce our observations. A large-scale structure of a few mas is clearly detected around the star with a typical flux relative contribution of 0.23 +- 0.02. Our best model is a co-rotational geometrical thin ring around the star as predicted by magnetically-confined wind shock models. The ring inner diameter is 8.2 +- 0.8 mas and the width is 0.6 +- 0.7 mas. The orientation of the rotation axis on the plane of the sky is PA = 60 +- 1 deg, while the best fit of the mean angular diameter of beta Cep gives UD[V] = 0.22 +- 0.05 mas. Our data are compatible with the predicted position of the close companion of beta Cep. These results bring additional constraints on the fundamental parameters and on the future MHD and asteroseismological models of the star.

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。

↑