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基于长期多历元资料的加速星识别研究

Identifying Accelerating Stars Based on Long-term Multi-epoch Data

  • 摘要: 已有观测研究发现, 约50%的双星系统具有超过百年的轨道周期, 这类具有长周期特性的双星系统通常子星间距离较大, 因此被称为宽距双星. 由于其长周期特性, 如果仅依赖短时间跨度的高精度观测数据, 难以得到这类双星的精确轨道参数, 甚至在识别环节也面临挑战. 为此, 构建了多历元星表, 在数据拟合过程中引入了基于观测误差和时间因子的新型加权算法, 有效提高了早期低精度观测数据的利用价值. 基于匀速直线运动的零假设, 采用卡方显著性检验对星表样本进行筛选, 最终识别出2214颗不符合零假设的加速星, 其中1565颗此前尚未被识别, 可作为新的宽距双星候选源. 与现有双星星表进行交叉验证表明, 所发展的基于早期星表的识别方法可实现对宽距双星的高效识别.

     

    Abstract: Previous observational investigations have revealed that roughly 50% of binary systems have orbital periods over a century. Binary systems with such long periods typically have large angular distances between the component stars, hence called wide binaries. It is then difficult to derive their precise orbital parameters by using only high precision observational data collected in recent several decade years. In fact, even identifying them as non-single stars is sometimes a challenge. Combining recent high precision and some early low precision star catalogs, we compile a multi-epoch star catalogue. And, based on observational errors and a time factor, we develop a novel weighting scheme, with which the weights of early low precision observational data in our least-square fitting are reasonably increased. Based on the null hypothesis of uniform rectilinear motion, the chi-square significance test is applied to the stars in the multi-epoch star catalog. As a result, 2214 accelerating stars, of which 1565 are new, are identified as candidates for wide binary stars. Upon cross-matching with existing binary star catalogs, the result suggests that the detection methodology based on early star catalogs and developed in this study shows remarkable superiority in terms of the identification efficiency of wide binary star systems.

     

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