Robo-AO Discovery and Basic Characterization of Wide Multiple Star Systems in the Pleiades, Praesepe, and NGC 2264 Clusters
Robo-AO Discovery and Basic Characterization of Wide Multiple Star Systems in the Pleiades, Praesepe, and NGC 2264 Clusters
复制标题
Robo-AO 昴宿星团、Praesepe 和 NGC 2264 星团中广域多星系统的发现和基本特征
DOI：
10.3847/1538-3881/aaa01e
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
J. Stauffer
中科院分区：
文献类型：
--
作者：
L. Hillenbrand;Celia Zhang;R. Riddle;C. Baranec;C. Ziegler;N. Law;J. Stauffer
我们识别并粗略描述了66个候选星星系统在昂宿星团，Praesepe和NGC 2264星星，基于机器人自适应光学成像数据使用Robo-AO在Palomar 60“望远镜。我们的成像对中只有10%是以前已知的。我们在红色光学波长处探测到伴星，物理分离范围从几十到几千个Au。为每个最终图像生成的三西格玛对比度曲线为任何未检测到的推定同伴提供了亮度比的上限。观测结果对最大对比度为0.66米的伴星敏感。在较小的间距下，2″处的平均（最佳）原始对比度为3.08（6 m），1″处为3.00（4.05），0.″5处为1.09（3 m）。点扩散函数减法可以在较近的分离中恢复几乎全部的对比度。对于检测到的候选二进制对，我们报告分离，位置角和相对幅度。理论等时线适当的昴星团和Praesepe集群，然后用于确定相应的二进制质量比，其范围从0.2到0.9英寸。对于我们的样本NGC 2264中大约太阳质量（FGK型）的恒星和昴星团和Praesepe中亚太阳质量（K和早期M型）的主恒星，总的双星频率测量为15.5% ± 2%。然而，鉴于尚未对灵敏度和完整性进行复杂和不确定的校正，应将该值视为这些集群中指定分离和质量比范围内真实二元分数的下限。
We identify and roughly characterize 66 candidate binary star systems in the Pleiades, Praesepe, and NGC 2264 star clusters, based on robotic adaptive optics imaging data obtained using Robo-AO at the Palomar 60″ telescope. Only ∼10% of our imaged pairs were previously known. We detect companions at red optical wavelengths, with physical separations ranging from a few tens to a few thousands of au. A three-sigma contrast curve generated for each final image provides upper limits to the brightness ratios for any undetected putative companions. The observations are sensitive to companions with a maximum contrast of ∼6m at larger separations. At smaller separations, the mean (best) raw contrast at 2″ is 3.ͫ8 (6m), at 1″ is 3.ͫ0 (4.ͫ5), and at 0.″5 is 1.ͫ9 (3m). Point-spread function subtraction can recover nearly the full contrast in the closer separations. For detected candidate binary pairs, we report separations, position angles, and relative magnitudes. Theoretical isochrones appropriate to the Pleiades and Praesepe clusters are then used to determine the corresponding binary mass ratios, which range from 0.2 to 0.9 in . For our sample of roughly solar-mass (FGK type) stars in NGC 2264 and sub-solar-mass (K and early M-type) primaries in the Pleiades and Praesepe, the overall binary frequency is measured at ∼15.5% ± 2%. However, this value should be considered a lower limit to the true binary fraction within the specified separation and mass ratio ranges in these clusters, given that complex and uncertain corrections for sensitivity and completeness have not been applied.