Eclipsing binaries (EBs) provide critical laboratories for empirically testing predictions of theoretical models of stellar structure and evolution. Pre-main-sequence (PMS) EBs are particularly valuable, both due to their rarity and the highly dynamic nature of PMS evolution, such that a dense grid of PMS EBs is required to properly calibrate theoretical PMS models. Analyzing multi-epoch, multi-color light curves for ~2400 candidate Orion Nebula Cluster (ONC) members from our Warm Spitzer Exploration Science Program YSOVAR, we have identified 12 stars whose light curves show eclipse features. Four of these 12 EBs are previously known. Supplementing our light curves with follow-up optical and near-infrared spectroscopy, we establish two of the candidates as likely field EBs lying behind the ONC. We confirm the remaining six candidate systems, however, as newly identified ONC PMS EBs. These systems increase the number of known PMS EBs by over 50% and include the highest mass (θ^1 Ori E, for which we provide a complete set of well-determined parameters including component masses of 2.807 and 2.797 M_☉) and longest-period (ISOY J053505.71–052354.1, P ~ 20 days) PMS EBs currently known. In two cases (θ^1 Ori E and ISOY J053526.88–044730.7), enough photometric and spectroscopic data exist to attempt an orbit solution and derive the system parameters. For the remaining systems, we combine our data with literature information to provide a preliminary characterization sufficient to guide follow-up investigations of these rare, benchmark systems.
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机译:渐进二进制文件(EB)提供了关键实验室,用于对恒星结构和演化理论模型的预测进行经验测试。由于它们的稀有性和PMS进化的高度动态性,前序序列(PMS)EB尤其有价值,因此需要一个密集的PMS EB网格才能正确地校准理论PMS模型。分析来自暖斯必泽勘探科学计划YSOVAR的大约2400个候选猎户座星云团(ONC)成员的多历时,多色光曲线,我们确定了12个恒星,其光曲线具有月食特征。这12个EB中有四个是先前已知的。用后续的光学和近红外光谱对我们的光曲线进行补充,我们确定了两个候选对象,它们可能是位于ONC后面的现场EB。但是,我们确定剩下的六个候选系统为新识别的ONC PMS EB。这些系统使已知PMS EB的数量增加了50%以上,并且包括最高质量(θ^ 1 Ori E,为此我们提供了一整套确定的参数,包括2.807和2.797M_☉的组分质量)和最长的当前已知的期限(ISOY J053505.71–052354.1,P〜20天)。在两种情况下(θ^ 1 Ori E和ISOY J053526.88–044730.7),存在足够的光度学和光谱数据来尝试进行轨道解并得出系统参数。对于其余系统,我们将数据与文献信息相结合,以提供足够的初步表征,以指导对这些稀有基准系统的后续调查。
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