Completing the Inventory of the Solar System

Scott Sheppard博士被授予美国国家科学基金会天文学和天体物理学博士后奖学金，在哈佛-史密森天体物理学中心开展研究和教育项目。为了帮助完成我们太阳系中小天体的清单，以了解行星的形成和演化，谢泼德博士将进行专门的调查，这是未来计划中的大型调查（如Pan-STARRS）无法获得的，因此是对其的补充。这些巡天将在柯伊伯带边缘以外寻找遥远的赛德娜类天体、南半球非常大的矮行星、极其微弱的柯伊伯带天体以及地球轨道内部的天体。这些精选的观测结果在智力上很重要，因为：1)像以前的冥王星一样，塞德娜可能只是遥远太阳系人口的冰山一角。塞德娜遥远的近日点目前并不符合我们对太阳系形成的看法。发现更多的塞德娜类型的天体可能会限制我们太阳的星团形成环境以及原始太阳星云的范围。最大的柯伊伯带天体非常罕见，但非常重要，因为它们的亮度使现代光谱学能够揭示它们的表面成分。3)柯伊伯带中最微弱的天体被认为是短周期彗星的前身。柯伊伯带的小端人口可能严重不足，使彗星的来源区域受到质疑。4)最后，地球轨道内部的近地天体对地球有严重的撞击危险，这一点尚未得到充分的探索。谢泼德还将与该中心的科学教育部门（SED）合作，开发和更新将在博物馆和研究所展出的交互式天文显示器。他还将领导一个由史密森学会运营的网络博客，讨论最近的天文学事件。

Dr. Scott Sheppard is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the Harvard-Smithsonian Center for Astrophysics. To help complete the inventory of small bodies in our solar system in order to understand planet formation and evolution, Dr. Sheppard will perform dedicated surveys unobtainable by and thus complimentary to future planned large surveys such as Pan-STARRS. The surveys will search for distant Sedna-type objects beyond the Kuiper-Belt edge, very large dwarf planets in the Southern Hemisphere, extremely faint Kuiper Belt objects, and objects interior of Earth's orbit. These selected observations are intellectually important because: 1) Like Pluto before, Sedna may just be the tip of the iceberg of a population in the distant Solar System. Sedna's distant perihelion does not currently fit into our ideas about solar system formation. Discovering more Sedna type objects may constrain our Sun's star cluster formation environment as well as the extent of the original solar nebula. 2) The largest Kuiper Belt objects are very rare but extremely important since their brightness allows modern spectroscopy to reveal their surface compositions. 3) The extremely faint and thus smallest Kuiper Belt objects are expected to be the progenitors of the short period comets. The small end of the Kuiper Belt population may be severely under abundant calling into question the source region of the comets. 4) Finally, the near Earth objects interior to Earth's orbit are a severe Earth impact hazard which has not yet been fully explored.Dr. Sheppard will also work with the Center's Science Education Department (SED) to develop and update interactive astronomy displays to be exhibited in museums and institutes. He will also lead a web blog run by the Smithsonian discussing recent astronomy events.