Nature2014-06-24 3:10 PM

矮行星Sedna不是孤立的 A Sedna-like body with a perihelion of 80 astronomical units


太阳系形成模型预测,遥远的、直径为1000公里的矮行星Sedna (在其最近点、即近日点距太阳76个天文单位),可能是在30-50个天文单位的距离处绕轨道运行的柯伊伯带天体与尚未看到的“外Oort云”(距太阳10,000个天文单位)之间的一个联系。现在,Chadwick Trujillo 和 Scott Sheppard报告了第二个与Sedna相似天体的存在,即2012 VP113,近日点为80个天文单位。这一发现证实,Sedna不是一个孤立的天体。这两个天体可能是一组“内Oort云”天体的成员,它们的数量可能超过太阳系中所有其他动态稳定的天体类群。


The observable Solar System can be divided into three distinct regions: the rocky terrestrial planets including the asteroids at 0.39 to 4.2 astronomical units (AU) from the Sun (where 1 AU is the mean distance between Earth and the Sun), the gas giant planets at 5 to 30 AU from the Sun, and the icy Kuiper belt objects at 30 to 50 AU from the Sun. The 1,000-kilometre-diameter dwarf planet Sedna was discovered ten years ago and was unique in that its closest approach to the Sun (perihelion) is 76 AU, far greater than that of any other Solar System body. Formation models indicate that Sedna could be a link between the Kuiper belt objects and the hypothesized outer Oort cloud at around 10,000 AU from the Sun. Here we report the presence of a second Sedna-like object, 2012 VP113, whose perihelion is 80 AU. The detection of 2012 VP113 confirms that Sedna is not an isolated object; instead, both bodies may be members of the inner Oort cloud, whose objects could outnumber all other dynamically stable populations in the Solar System.






Nature Magazine

0 Following 27 Fans 0 Projects 626 Articles


Meristems encompass stem/progenitor cells that sustain postembryonic growth of all plant organs. How meristems are activated and sustained by nutrient

Read More

Transcription of ribosomal RNA by RNA polymerase (Pol) I initiates ribosome biogenesis and regulates eukaryotic cell growth. The crystal structure of P

Read More

Abstract The effect of anthropogenic aerosols on cloud droplet concentrations and radiative properties is the source of one of the largest uncertainti

Read More

Abstract Ecological and societal disruptions by modern climate change are critically determined by the time frame over which climates shift beyond his

Read More

Abstract Evidence from Greenland ice cores shows that year-to-year temperature variability was probably higher in some past cold periods, but there is

Read More

Abstract The land and ocean act as a sink for fossil-fuel emissions, thereby slowing the rise of atmospheric carbon dioxide concentrations1. Although t

Read More

论文摘要 人们已经非常清楚生物多样性对初级生产力等生态系统功能有一个积极影响,但它对植物凋落物的多样性和分解植物凋落物的生物的多样性的影响却不是很清楚。Stephan H?ttenschwiler及同事对从亚北极到热带、包括水生生态系统和陆地生态系统在内的五个地点所进行的并行操纵实验中的凋落物多样性进

Read More

论文摘要 FANTOM5 (即“哺乳动物基因组-5的功能注解”) 是一个大型国际合作项目的第5大阶段,其目标是分析定义每个人类细胞类型的转录调控网络。本期Nature上的两篇Articles论文发表了该项目的一些最新结果。第一篇论文利用FANTOM5项目组的组织和原代细胞样本来定义整个人体中活性的、在

Read More

论文摘要 有证据表明,血管 (尤其是它们的内皮细胞) 控制器官的生长、平衡和再生。在本期Nature上发表的两篇论文中,Ralf Adams及同事证明,骨头血管含有专门支持骨成熟和再生的内皮细胞。Anjali Kusumbe等人在小鼠骨骼系统内识别出一个在介导骨生长中起关键作用的毛细血管亚型。这些血管

Read More

论文摘要 CD4 T细胞(携带能够识别被病毒感染的细胞表面上的CD4抗原的受体的辅助T细胞)的丧失是艾滋病发病的根源。在这项研究中,Warner Greene等人识别出静止的淋巴CD4 T细胞在HIV感染过程中被耗尽的机制。利用保持了天然淋巴环境的人淋巴组织的体外培养,本文作者发现,失败的病毒复制触发

Read More