论文标题
集群年龄实验（情况）。 viii。球状簇的年龄和距离47 TUC与对两个脱落的二进制的分析分析
The Cluster Ages Experiment (CASE). VIII. Age and Distance of the Globular Cluster 47 Tuc from the Analysis of Two Detached Eclipsing Binaries
论文作者
论文摘要
我们使用球状簇47 TUC中黯然失色的二进制E32的光度和光谱观测来得出组分恒星的质量，半径和亮度。该系统的轨道周期为40.9 d，这是一个具有E = 0.24的偏心轨道，被证明是群集的成员或最近的Escaper。我们获得MP = 0.862（5）MSUN，RP = 1.183（3）RSUN，LP = 1.65（5）lsun the Primary，MS = 0.827（5）MSUN，Rs = 1.004（4）RSUN，LS = 1.14（4）LSUN的次级LSUN。基于这些数据和对47 TUC中二进制V69的早期分析，我们测量了与组件恒星距离模量群体的距离，并独立于颜色 - 表面亮度校准。我们分别获得4.55（3）和4.50（7）KPC-基于GAIA DR2可视性的最新估计值在1 Sigma中兼容。通过比较两个二进制文件的M- r图和47 TUC的色彩图与达特茅斯模型等速线，我们估计集群的年龄为12.0 pm 0.5 gyr，群集的氦气丰度约为y约0.25。
We use photometric and spectroscopic observations of the eclipsing binary E32 in the globular cluster 47 Tuc to derive the masses, radii, and luminosities of the component stars. The system has an orbital period of 40.9 d, a markedly eccentric orbit with e = 0.24, and is shown to be a member of or a recent escaper from the cluster. We obtain Mp = 0.862(5) Msun , Rp = 1.183(3) Rsun , Lp = 1.65(5) Lsun for the primary and Ms = 0.827(5) Msun , Rs = 1.004(4) Rsun , Ls = 1.14(4) Lsun for the secondary. Based on these data and on an earlier analysis of the binary V69 in 47 Tuc we measure the distance to the cluster from the distance moduli of the component stars, and, independently, from a color - surface brightness calibration. We obtain 4.55(3) and 4.50(7) kpc, respectively - values compatible within 1 sigma with recent estimates based on Gaia DR2 parallaxes. By comparing the M - R diagram of the two binaries and the color-magnitude diagram of 47 Tuc to Dartmouth model isochrones we estimate the age of the cluster to be 12.0 pm 0.5 Gyr, and the helium abundance of the cluster to be Y approx 0.25.
