标题： 年轻恒星双星的天体物理学 显示英文标题

标题： Astrophysics of Young Star Binaries

摘要： 本文描述了我们对近距离前主序双星中各个组成部分的天体物理学研究。 我们观察了17个系统中的两颗恒星，这些系统位于4个附近的恒星形成区域，使用低分辨率（R=760）的红外光谱和测光法。 对于29个组成部分，我们检测到了光球吸收线，并能够确定光谱类型、消光、K波段过量和光度。 另外5个物体显示了无特征或纯发射线光谱。 在约50%的系统中，主星的消光和K波段过量超过了伴星的。 通过将这些29个物体放置在叠加有理论前主序星轨迹的赫罗图上，确定了它们的质量和年龄。 大多数双星似乎同时形成。 年龄跨度为5×10^5到1×10^7年。 推导出的质量从次恒星质量0.06 M_sun到2.5 M_sun不等，质量比从M_2/M_1=0.04到1.0。 十四颗恒星显示出原恒星盘的证据。 对于具有原恒星物质的恒星，K波段过量与K-L颜色之间存在良好的相关性。 显示英文摘要

摘要： This paper describes our study of the astrophysics of individual components in close pre-main-sequence binaries. We observed both stars in 17 systems, located in 4 nearby star forming regions, using low-resolution (R=760), infrared spectroscopy and photometry. For 29 components we detected photospheric absorption lines and were able to determine spectral type, extinction, K-band excess, and luminosity. The other 5 objects displayed featureless or pure emission line spectra. In ~50 % of the systems, the extinction and K-band excess of the primary stars dominate those of the secondaries. Masses and ages were determined for these 29 objects by placing them on the H-R diagram, overlaid with theoretical pre-main-sequence tracks. Most of the binaries appear to be coeval. The ages span 5x10^5 to 1x10^7 years. The derived masses range from the substellar, 0.06 M_sun, to 2.5 M_sun, and the mass ratios from M_2/M_1=0.04 to 1.0. Fourteen stars show evidence of circumstellar disks. The K-band excess is well correlated with the K-L color for stars with circumstellar material.