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arXiv 0907.1198astro-ph.SR
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CoRoT星震目标的精确基本参数:类太阳恒星HD 49933,HD 175726,HD 181420和HD 181906

Accurate fundamental parameters of CoRoT asteroseismic targets: the solar-like stars HD 49933, HD 175726, HD 181420 and HD 181906

H. Bruntt

摘要:

CoRoT卫星提供了几颗类太阳恒星的高质量光变曲线。对光变曲线的分析提供了振荡频率,使探测恒星内部成为可能。然而,对恒星基本参数的额外限制对于理论建模的成功是重要的。我们将估计在小行星地震场观测到的前四个类太阳目标的基本参数(质量、半径和光度)。此外,我们将确定它们的有效温度,金属丰度和详细的丰度模式。为了限制恒星的质量、半径和年龄,我们使用SHOTGUN软件,该软件将恒星在赫兹-罗素图中的位置与理论演化模型进行比较。该方法考虑了观测参数的不确定性,包括从类太阳振荡确定的大分离。我们确定的有效温度和丰度模式的恒星从高分辨率光谱的分析。我们已经确定了四个CoRoT目标的质量,半径和光度分别在5- 10%,2- 4%和5- 13%之间。恒星光谱的质量决定了我们对有效温度的限制程度。对于两个最好的光谱,我们得到低于60 K的1-sigma不确定度,而对于另外两个100-150 K。三颗恒星的表面重力不确定度小于0.08 dex,而HD 181906的表面重力不确定度为0.15 dex。不确定度较大的原因是光谱有两个分量,光度比为Lp/Ls = 0.50+-0.15。虽然依巴谷天体测量数据强烈表明它是一颗双星,但我们发现证据表明,较暗的恒星可能是一颗背景恒星,因为它不那么明亮,但更热。

英文摘要:

The CoRoT satellite has provided high-quality light curves of several solar-like stars. Analysis of the light curves provides oscillation frequencies that make it possible to probe the interior of the stars. However, additional constraints on the fundamental parameters of the stars are important for the theoretical modelling to be successful. We will estimate the fundamental parameters (mass, radius and luminosity) of the first four solar-like targets to be observed in the asteroseismic field. In addition, we will determine their effective temperature, metallicity and detailed abundance pattern. To constrain the stellar mass, radius and age we use the SHOTGUN software which compares the location of the stars in the Hertzsprung-Russell diagram with theoretical evolution models. This method takes into account the uncertainties of the observed parameters including the large separation determined from the solar-like oscillations. We determine the effective temperatures and abundance patterns in the stars from the analysis of high-resolution spectra. We have determined the mass, radius and luminosity of the four CoRoT targets to within 5-10 percent, 2-4 percent and 5-13 percent, respectively. The quality of the stellar spectra determines how well we can constrain the effective temperature. For the two best spectra we get 1-sigma uncertainties below 60 K and for the other two 100-150 K. The uncertainty on the surface gravity is less than 0.08 dex for three stars while for HD 181906 it is 0.15 dex. The reason for the larger uncertainty is that the spectrum has two components with a luminosity ratio of Lp/Ls = 0.50+-0.15. While Hipparcos astrometric data strongly suggest it is a binary star we find evidence that the fainter star may be a background star, since it is less luminous but hotter.

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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