Young Star Dynamical Mass Ratios and Masses

虽然地球围绕着一颗恒星运行，但我们银河系中的大多数恒星都位于双星或多星系统中--由两颗或更多恒星组成的引力相互束缚的星团。这两颗双星围绕对方运行一周的时间可以从几小时到几天、几周、几个月、几年或几千年不等。最接近的两颗恒星的轨道需要几个月或更短的时间，它们组成了一种特殊的类别，称为“光谱双星”。它们移动得如此之快，以至于可以测量每颗恒星的速度，从这些速度我们可以确定它们的质量比。在非常年轻、新形成的恒星中，这些光谱双星提供了一种方法来测量恒星生命周期中一个鲜为人知的时期的最基本的恒星性质-质量。这可以帮助我们在一个关键时期--行星形成的开始--校准恒星基本性质之间的关系。在这个项目中，PI将观察140个候选年轻光谱双星的样本，以确认它们的多重性并测量真实对的质量比。这项研究将由PI与本科生和初级研究生合作进行，其中一些人来自传统上在天文学中代表较少的群体。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很重要。通常，这是通过将H-R图上恒星的位置与年轻恒星演化的理论轨迹进行比较来完成的。然而，各种各样的可用计算预测了年轻时可能存在的大范围恒星质量。国际和平研究所在这一领域的工作有助于重新引起人们对改进这些模式的兴趣。在这个项目中，她将观察140个候选年轻光谱双星的样本，以利用MMT望远镜上的多目标可见光光谱来确认它们的多重性，并使用发现频道望远镜测量具有3个红外光谱纪元的真实双星对的质量比。

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.