Using Orbital Effects to Break the Close/Wide Degeneracy in Binary-lens Microlensing Events
Using Orbital Effects to Break the Close/Wide Degeneracy in Binary-lens Microlensing Events
复制标题
利用轨道效应打破双透镜微透镜事件中的近/宽简并性
DOI：
10.1088/0004-637x/764/1/64
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发表时间：
2013
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et al.
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作者：
I-G. Shin;et al.
微透镜可以为研究双星提供一个重要的工具，特别是那些由暗或暗物体组成的双星。然而，由于透镜方程中固有的对称性，紧密双星(S；1)和宽双星(S>；1)之间的众所周知的简并性常常阻碍了对双透镜光线曲线的准确分析。这里，S是归一化的投影二进制分离。在本文中，我们提出了一种利用透镜轨道运动对透镜光曲线的影响来解决近/宽简并问题的方法。这种方法是基于这样一个事实，即轨道效应对于近双星来说往往很重要，而对于宽双星来说它可以忽略不计。我们通过一个实际观测的双透镜事件MOA-2011-BLG-040/OGLE-2011-BLG-0001证明了该方法的有效性，该事件遭受着严重的近/宽简并。由此，我们能够唯一地确定该透镜由距离地球3.5kpc的K型和M型矮星组成。∼3.5kpc。
Microlensing can provide an important tool to study binaries, especially those composed of faint or dark objects. However, accurate analysis of binary-lens light curves is often hampered by the well-known degeneracy between close (s< 1) and wide (s> 1) binaries, which can be very severe due to an intrinsic symmetry in the lens equation. Here, s is the normalized projected binary separation. In this paper, we propose a method that can resolve the close/wide degeneracy using the effect of a lens orbital motion on lensing light curves. The method is based on the fact that the orbital effect tends to be important for close binaries while it is negligible for wide binaries. We demonstrate the usefulness of the method by applying it to an actually observed binary-lens event MOA-2011-BLG-040/OGLE-2011-BLG-0001, which suffers from severe close/wide degeneracy. From this, we are able to uniquely specify that the lens is composed of K-and M-type dwarfs located∼ 3.5 kpc from the Earth.