Collaborative Research: The Evolution of Winds in Dust Disks Around Stars

行星是由气体和尘埃盘中的物质形成的，这些物质曾经围绕着它们所绕的恒星。这些圆盘形成的方式以及物质在圆盘上的分布方式既影响了物质向恒星本身添加的速度，也影响了圆盘上可以形成的行星类型。圆盘风在这种物质分散的方式中起着重要作用。在这项研究中，研究人员建立在他们早期的工作基础上，他们观察了33个磁盘的磁盘风。他们观察到风的两个部分：由磁/电相互作用驱动的风和由温差驱动的风。有了这笔资金，研究人员将扩大他们的研究范围，包括大量更老的磁盘，目的是测量磁电过程对风的驱动程度，以及热加热对风的驱动程度。这个项目符合国家利益，因为它扩大了我们对其他恒星周围行星系统形成背后的科学的理解。一名研究生、一名博士后和至少三名本科生将参与本研究。调查人员还将参加亚利桑那大学的K-12教师研讨会，接触西班牙裔和美洲原住民社区。一年一度的史密斯夏季科学与工程项目将为来自世界各地的高中女生开设为期两周的天文学课程。对金牛座33个圆盘的光学[OI]发射线的分析揭示了两个低速运动成分，其中一个（宽成分）可能追踪磁流体动力（MHD）驱动的风，而另一个（窄成分）可能与热驱动的风有关。研究人员将通过测量mhd驱动风和热驱动风的相对比例来确定盘风是如何演变的。他们还将通过圆盘演化和扩散的主要阶段测量风质量损失率。他们将把对[OI]谱线的分析扩展到更进化的圆盘样本，包括更多带有尘埃腔的圆盘，并分析其中一个蓝色[SII]跃迁，以澄清对[OI]发射的热贡献。

Planets formed from material in disks of gas and dust that once surrounded the stars they orbit. The way that these disks form and how material is spread throughout the disks affect both how quickly material is added to the stars themselves and what types of planets can form in the disks. Disk winds play a major role in the way this material is dispersed. In this study, the investigators build on their earlier work where they observed the disk winds in 33 disks. They observed two parts to the winds: a wind driven by magnetic/electric interactions and a wind driven by temperature differences. With this grant the investigators will extend their study to include a large number of much older disks with the goals of measuring how much the magnetic/electric process drives with wind and how much the thermal heating drives the wind. This project serves the national interest as it expands our understanding of the science behind the formation of planetary systems around other stars. A graduate student, a postdoc, and at least three undergraduate students will participate in this study. The investigators will also participate in a K-12 teacher workshop at The University of Arizona, reaching Hispanic and Native American communities. A two-week long astronomy class will be taught to high school girls from around the world in the annual Smith Summer Science and Engineering Program.The analysis of optical [OI] emission lines for the 33 disks in Taurus reveals two low-velocity kinematic components, one of which (broad component) likely traces a magnetohydrodynamic (MHD)-driven wind while the other (narrow component) might be associated with a thermally-driven wind. The investigators will establish empirically how disk winds evolve by measuring the relative proportion of MHD-driven and thermally-driven winds. They will also measure wind mass loss rates through the main stages of disk evolution and dispersal. They will extend their analysis of the [OI] lines to a sample of more evolved disks, including more disks with dust cavities, and analyze one of the blue [SII] transitions to clarify the thermal contribution to the [OI] emission.