盖亚会告诉我们关于银河系圆盘的什么？
What will Gaia tell us about the Galactic disk?
摘要：
盖亚将为多达10亿颗恒星提供从10到1000微弧秒的精确度范围内的视差和自行。其中大部分将是盘星：对于一颗6 kpc的未红化K巨星，它将测量精确到15%的距离和大约1 km/s的横向速度。盖亚将在整个HR图上观测银河系结构的示踪物，包括造父变星、天琴座RR、白矮星、F矮星和HB星。机载低分辨率分光光度计将允许-除了Teff估计-矮/巨歧视，金属丰度测量和灭绝的决定。那么，盖亚将首次为我们提供这些示踪剂的3D空间/属性图和至少一个2D速度图（对于较亮的恒星也将获得RV）。这将是一个信息的金矿，从中可以了解银河系圆盘的起源和演化。我简要回顾了盖亚任务，然后展示了预期的天体测量精度如何转化为距离和速度精度和统计数据。我研究盖亚应该对一些与银河系圆盘相关的科学领域产生的影响。我将讨论如何更好地确定旋臂的位置和模式的速度，再加上更好地重建太阳的轨道在过去的十亿年（从集成通过盖亚测量的引力势）将使我们能够评估可能的作用，在冰河时代和地球上的大规模灭绝的旋臂交叉。
英文摘要：
Gaia will provide parallaxes and proper motions with accuracy ranging from 10 to 1000 microarcsecond on up to one billion stars. Most of these will be disk stars: for an unreddened K giant at 6 kpc, it will measure the distance accurate to 15% and the transverse velocity to an accuracy of about 1 km/s. Gaia will observe tracers of Galactic structure across the whole HR diagram, including Cepheids, RR Lyrae, white dwarfs, F dwarfs and HB stars. Onboard low resolution spectrophotometry will permit -- in addition to a Teff estimate -- dwarf/giant discrimination, metallicity measurement and extinction determination. For the first time, then, Gaia will provide us with a 3D spatial/properties map and at least a 2D velocity map of these tracers (RVs will be obtained too for brighter stars.) This will be a goldmine of information from which to learn about the origin and evolution of the Galactic disk. I briefly review the Gaia mission, and then show how the expected astrometric accuracies translate into distance and velocity accuracies and statistics. I examine the impact Gaia should have on a few scientific areas relevant to the Galactic disk. I discuss how a better determination of the spiral arm locations and pattern speed, plus a better reconstruction of the Sun's orbit over the past billion years (from integration through the Gaia-measured gravitational potential) will allow us to assess the possible role of spiral arm crossings in ice ages and mass extinctions on the Earth.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
