Multiplicity Among Young Stars

恒星天体物理学的一个主要问题是如何调和这样一个发现：人们在天空中看到的至少一半的成熟（主序）恒星实际上是接近的双星，或“双星”，而仍在形成的恒星，金牛座T星，似乎绝大多数是单星。多亏了这位首席研究员（PI）之前在nsf的支持下所做的工作，这种差异现在看来显然是由于很难用传统的光谱技术在非常年轻的恒星中发现双星现象。在红外波段工作，PI利用月球作为“刀刃”来隐藏（日食）天空中金牛座区域的主序前恒星，以确定它们是单星还是双星。在过去的几年里，他发现13/28的被遮挡的金牛座T星是双星或三星系统的成员。在接下来的几年里，随着月球轨道向南运行，PI计划将这项工作扩展到蛇夫座区域的金牛座T星。除了增加年轻双星的统计数据外，PI计划同时从夏威夷和基特峰两个地点观察一些掩星事件。这项工作有望澄清太阳型恒星形成双星的条件，而不是具有行星系统的单星。

A major problem in stellar astrophysics has been reconciling the discovery that at least one half of the mature (main sequence) stars one sees in the skies are actually close double stars, or "binary" stars, whereas stars that are still forming, T Tauri stars, seem overwhelmingly to be single stars. Thanks largely to previous NSF-supported work by this Principal Investigator (PI) this discreprancy now seems clearly due to the difficulty of discovering binarity among very young stars from conventional spectroscopic techniques. Working at infrared wavelengths, the PI has used the moon as a "knife edge" to occult (eclipse) pre-main sequence stars in the Taurus region of the sky to determine whether they are single or double stars. In the last few years he has found that 13/28 of occulted T Tauri stars are members of double or triple star systems. The PI proposes to extend this work to T Tauri stars in the Ophiuchus region of the sky as the Moon's orbit progresses southward over the next few years. In addition to adding to the statistics of young binary stars, the PI plans to observe some of the occultation events from two locations simultaneously, Hawaii and Kitt Peak. This work is expected to clarify the conditions under which solar-type stars form binary stars as opposed to single stars with planetary systems.