arXiv 0910.34932009-10-19astro-ph.SR

M星大气速度的三维模拟及其对分子FeH谱线的影响

3D simulations of M star atmosphere velocities and their influence on molecular FeH lines

S. Wende, A. Reiners, H. -G. Ludwig

备注：: 14 pages, 17 figures, 3 tables, accepted by Astronomy & Astrophysics
DOI：: 10.1051/0004-6361/200913149

摘要：

我们提出了一个调查的速度场在早期到晚期M型星流体动力学模型，我们模拟它们的影响FeH分子线的形状。M星模型参数的范围为logg = 3.0 - 5.0，Teff = 2500 K-4000 K。我们的目的是表征Teff和日志g -依赖的速度场，并表示它们在微观和宏观湍流速度在一维意义上。我们还提出了一个直接的比较三维流体动力学速度场和一维湍流速度。的速度场强烈地影响线的形状FeH，这是我们的目标，给出一个粗略的估计的日志g和Teff参数范围内的3D频谱合成是必要的，其中1D合成就足够了。为了计算M星结构模型，我们采用三维辐射流体动力学（RHD）代码CO 5 BOLD。这些模型的光谱合成与线合成代码LINFOR 3D。我们描述的3D速度场的高斯标准偏差，并将它们投影到视线上，包括几何和边缘变暗的影响。微观和宏观湍流速度分别用“增长曲线”法和高斯速度剖面卷积法确定。为了表征FeH线的log g和Teff依赖性，考虑了等效宽度、线宽度和线深度。M星的速度场强烈依赖于log g和Teff。它们随着log g的减小和Teff的增加而变得更强。

英文摘要：

We present an investigation of the velocity fields in early to late M-type star hydrodynamic models, and we simulate their influence on FeH molecular line shapes. The M star model parameters range between log g of 3.0 - 5.0 and Teff of 2500 K and 4000 K. Our aim is to characterize the Teff- and log g -dependence of the velocity fields and express them in terms of micro- and macro-turbulent velocities in the one dimensional sense. We present also a direct comparison between 3D hydrodynamical velocity fields and 1D turbulent velocities. The velocity fields strongly affect the line shapes of FeH, and it is our goal to give a rough estimate for the log g and Teff parameter range in which 3D spectral synthesis is necessary and where 1D synthesis suffices. In order to calculate M-star structure models we employ the 3D radiative-hydrodynamics (RHD) code CO5BOLD. The spectral synthesis on these models is performed with the line synthesis code LINFOR3D. We describe the 3D velocity fields in terms of a Gaussian standard deviation and project them onto the line of sight to include geometrical and limb-darkening effects. The micro- and macro-turbulent velocities are determined with the "Curve of Growth" method and convolution with a Gaussian velocity profile, respectively. To characterize the log g and Teff dependence of FeH lines, the equivalent width, line width, and line depth are regarded. The velocity fields in M-stars strongly depend on log g and Teff. They become stronger with decreasing log g and increasing Teff.

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。

摘要：

英文摘要：

相关论文