arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节（Veterans Day），12 日无更新
arXiv 0910.4037astro-ph.SR
收藏

CoRoT目标HD 49933：2-理论模式振幅与观测值的比较

The CoRoT target HD 49933: 2- Comparison of theoretical mode amplitudes with observations

R. Samadi, H. -G. Ludwig, K. Belkacem, M. J. Goupil, O. Benomar, B. Mosser, M. -A. Dupret, F. Baudin, T. Appourchaux, E. Michel

备注：
8 pages, 3 figures (B-W and color), accepted for publication in Astronomy & Astrophysics. Corrected typo in Eq. (4). Updated references. Language improvements
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

从地震数据获得的CoRoT的明星HD 49933是可能的，因为太阳，约束模型的激励声模式的湍流对流。我们比较了随机激励模型中描述的文件I（arXiv：0910.4027）与星震学数据HD 49933，一颗恒星，而金属贫乏，显着比太阳热。使用的模式线宽测量的CoRoT HD 49933和理论模式的激励率计算在纸我，我们推导出预期的表面速度振幅的声学模式检测HD 49933。使用校准的准绝热近似的模式振幅强度的速度，我们得到的预期值的模式振幅强度。我们的振幅计算是在1西格玛误差酒吧的模式表面速度谱与HARPS摄谱仪。从CoRoT数据中导出的HD 49933的强度模式振幅也发现了相同的情况。另一方面，在高频率下，我们的计算显着偏离CoRoT和HARPS测量。我们表明，假设太阳的金属丰度，而不是恒星的实际金属丰度将导致更大的差异与地震数据。此外，假设“新”太阳化学混合物的计算比假设“旧”太阳化学混合物的计算更符合地震数据。这些结果验证，在一个恒星的情况下显着热比太阳和阿尔法Cen A，在模型中的随机激励的主要假设。然而，频繁出现的差异突出了建模的一些缺陷，其根源仍有待了解。

英文摘要：

From the seismic data obtained by CoRoT for the star HD 49933 it is possible, as for the Sun, to constrain models of the excitation of acoustic modes by turbulent convection. We compare a stochastic excitation model described in Paper I (arXiv:0910.4027) with the asteroseismology data for HD 49933, a star that is rather metal poor and significantly hotter than the Sun. Using the mode linewidths measured by CoRoT for HD 49933 and the theoretical mode excitation rates computed in Paper I, we derive the expected surface velocity amplitudes of the acoustic modes detected in HD 49933. Using a calibrated quasi-adiabatic approximation relating the mode amplitudes in intensity to those in velocity, we derive the expected values of the mode amplitude in intensity. Our amplitude calculations are within 1-sigma error bars of the mode surface velocity spectrum derived with the HARPS spectrograph. The same is found with the mode amplitudes in intensity derived for HD 49933 from the CoRoT data. On the other hand, at high frequency, our calculations significantly depart from the CoRoT and HARPS measurements. We show that assuming a solar metal abundance rather than the actual metal abundance of the star would result in a larger discrepancy with the seismic data. Furthermore, calculations that assume the ``new'' solar chemical mixture are in better agreement with the seismic data than those that assume the ``old'' solar chemical mixture. These results validate, in the case of a star significantly hotter than the Sun and Alpha Cen A, the main assumptions in the model of stochastic excitation. However, the discrepancies seen at high frequency highlight some deficiencies of the modelling, whose origin remains to be understood.

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。

↑