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arXiv 1002.4503astro-ph.GAastro-ph.SR
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确定疏散星团金属丰度的统计方法

A statistical method to determine open cluster metallicities

Harald Poehnl, Ernst Paunzen

摘要:

对疏散星团金属丰度的研究有助于理解整个银河系的局部恒星形成和演化。它的金属丰度梯度是全球意义上的银河系形成的重要示踪剂。由于疏散星团可以用统计的方法处理,所以聚类平均值的误差最小。我们的最终目标是一个半自动的统计鲁棒的方法来估计的统计上显着的数量的疏散星团的基础上约翰逊BV数据的成员,一个算法,可以很容易地扩展到其他光度系统的系统调查的金属丰度。该方法结合了不同金属丰度的演化网格和有效温度和光度的校准。通过聚类参数(年龄、红化和距离),可以从统计学的角度估计金属丰度。迭代过程包括初始输入参数的内在一致性检查,并允许我们修改它们。我们广泛地测试了方法与公布的数据毕宿星团和选择16个疏散星团在1000 pc的太阳周围可用的和可靠的约翰逊BV测量。此外,伯克利29号,距离约15kpc被选中。对于几个目标,我们能够将我们的结果与发表的结果进行比较,这些结果产生了非常好的一致性(包括Berkeley 29)。

英文摘要:

The study of open cluster metallicities helps to understand the local stellar formation and evolution throughout the Milky Way. Its metallicity gradient is an important tracer for the Galactic formation in a global sense. Because open clusters can be treated in a statistical way, the error of the cluster mean is minimized. Our final goal is a semi-automatic statistical robust method to estimate the metallicity of a statistically significant number of open clusters based on Johnson BV data of their members, an algorithm that can easily be extended to other photometric systems for a systematic investigation. This method incorporates evolutionary grids for different metallicities and a calibration of the effective temperature and luminosity. With cluster parameters (age, reddening and distance) it is possible to estimate the metallicity from a statistical point of view. The iterative process includes an intrinsic consistency check of the starting input parameters and allows us to modify them. We extensively tested the method with published data for the Hyades and selected sixteen open clusters within 1000pc around the Sun with available and reliable Johnson BV measurements. In addition, Berkeley 29, with a distance of about 15kpc was chosen. For several targets we are able to compare our result with published ones which yielded a very good coincidence (including Berkeley 29).

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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