论文标题
大规模偏心二进制的Apsidal运动：CPD-41 $^\ Circ $ 7742和HD 152218的案例。
Apsidal motion in massive eccentric binaries: The case of CPD-41$^\circ$7742, and HD 152218 revisited
论文作者
论文摘要
本文是密切偏心大规模二元系统中Apsidal运动的研究的一部分，该系统旨在限制恒星的内部结构。我们专注于二进制CPD-41°7742和Revisit HD152218。过去对CPD-41°7742的独立研究表明，在轨道的围龙的经度中，差异很大，暗示了存在急性运动的存在。我们对所有观察数据进行一致的分析，并明确考虑APSidal运动。我们使用CPD-41°7742的光谱和光度观察来推断基本恒星和二进制参数的值。我们在观察时期对光谱进行分解方法，同时衍生RV，并重建单个恒星光谱。这些通过CMFGEN分析以确定恒星性质。我们以两种方式确定APSidal运动速率：我们将RV与文献中报道的RV进行补充，并使用初级和二次蚀之间的相移。光曲线通过夜幕降临，以限制轨道倾斜度和恒星质量。恒星结构和进化模型是用CLE构建的。采用了混合的不同处方。分析了HD152218的光度数据，并构建了恒星进化模型。二进制CPD-41°7742以15.38+0.42-0.51°yr-1的速率显示Apsidal运动。我们对CPD-41°7742的观察数据明确考虑APSIDAL运动的分析使我们能够解释Periastron纵向的差异。年龄估计与NGC 6231中其他大规模二进制的估计值非常吻合。这项研究证实了在恒星进化模型中需要增强混合以重现观察性恒星特性的必要性。这指向比通常考虑的更大的对流芯。
This paper is part of a study of the apsidal motion in close eccentric massive binary systems, which aims to constrain the internal structure of the stars. We focus on the binary CPD-41°7742 and revisit HD152218. Independent studies of CPD-41°7742 in the past showed large discrepancies in the longitude of periastron of the orbit, hinting at the presence of apsidal motion. We perform a consistent analysis of all observational data, explicitly accounting for the apsidal motion. We use spectroscopic and photometric observations of CPD-41°7742 to infer values for the fundamental stellar and binary parameters. We apply a disentangling method to the spectra to simultaneously derive the RVs at the times of observation and reconstruct the individual stellar spectra. These are analysed by means of CMFGEN to determine the stellar properties. We determine the apsidal motion rate in two ways: We complement our RVs with those reported in the literature and we use the phase shifts between the primary and secondary eclipses. The light curves are analysed by means of Nightfall to constrain the orbital inclination and stellar masses. Stellar structure and evolution models are constructed with Cles. Different prescriptions for the mixing are adopted. Photometric data of HD152218 are analysed and stellar evolution models are built. The binary CPD-41°7742 displays apsidal motion at a rate of 15.38+0.42-0.51° yr-1. Our analysis of the observational data of CPD-41°7742 explicitly accounting for the apsidal motion allows us to explain the discrepancy in periastron longitudes. The age estimates are in good agreement with estimates obtained for other massive binaries in NGC 6231. This study confirms the need for enhanced mixing in the stellar evolution models to reproduce the observational stellar properties; this points towards larger convective cores than usually considered.
