Young Star Dynamical Mass Ratios and Masses

虽然地球绕着一颗恒星运行，但我们银河系中的大多数恒星都位于双星或多星系统中——由两颗或更多的恒星组成的群体，它们相互之间受到引力的束缚。双星系统中的两颗恒星绕彼此完成一个完整的轨道所需的时间可以是几小时到几天、几周、一个月、几年，甚至几千年。最接近的双星，其轨道需要几个月或更短的时间，构成了一个特殊的类别，称为“光谱双星”。它们移动得如此之快，以至于我们可以测量每颗恒星的速度，并从速度中确定它们的质量比。在非常年轻的新形成的恒星中，这些光谱双星提供了一种方法来测量最基本的恒星属性，质量，在恒星生命周期的一个鲜为人知的时期。这可以帮助我们在一个关键时期校准基本恒星特性之间的关系：行星形成的开始。在这个项目中，PI将观察140个候选的年轻光谱双星的样本，以确认它们的多样性，并测量真正的双星的质量比。这项研究将由PI与本科生和初级研究生合作进行，其中一些学生来自传统上在天文学中代表性不足的群体。测量年轻恒星的质量比和质量对于理解恒星和双星形成的物理过程非常重要。通常，这是通过比较恒星在H-R图上的位置和年轻恒星演化的理论轨迹来完成的。然而，各种各样的可用计算预测了很大范围内年轻恒星的可能质量。PI在这一领域的工作有助于重新唤起人们对改进这些模型的兴趣。在这个项目中，她将对140个候选年轻双星进行观测，利用MMT望远镜的多目标可见光光谱来确认它们的多重性，并利用探索频道望远镜的3次红外光谱来测量真正的双星的质量比。

Although Earth orbits a single star, most stars in our Galaxy are located in binary or multiple systems - groups of two or more stars that are gravitationally bound to each other. The time it takes the two stars in a binary to complete one full orbit around each other can be anywhere from hours to days, weeks, month, years, or millennia. The stars in the closest pairs with orbits that take months or less, comprise a special category called "spectroscopic binaries". They move so rapidly that it is possible to measure the velocities of each star, and from the velocities we can determine the ratio of their masses. Among very young, newly formed stars, these spectroscopic binaries provide a way to measure the most fundamental stellar property, mass, during a poorly understood period in the life-cycle of stars. This can help us calibrate the relationships between fundamental stellar properties at a key epoch: the onset of planet formation. Inthis program, the PI will observe a sample of 140 candidate young spectroscopic binaries to confirm theirmultiplicity and to measure the mass ratios of the bona fide pairs. This research will be carried out by the PI in collaboration with undergraduate and junior graduate students, some of them from groups traditionally underrepresented in astronomy.Measuring the mass ratios and masses of young stars is important for understanding the physical processes of star and binary formation. Usually, this is accomplished by comparing the locations of stars on an H-R diagram to theoretical tracks of young star evolution. However, the wide variety of available calculations predict a large range of possible stellar masses at young ages. The PI's work in this area has helped to renew interest in improving these models. In this program, she will observe a sample of 140 candidate young spectroscopic binaries to confirm their multiplicity with multi-object visible light spectroscopy on the MMT Telescope and to measure the mass ratios of the bona fide pairs with 3 epochs of infrared spectroscopy using the Discovery Channel Telescope.