自然杂志 ›› 2013, Vol. 35 ›› Issue (3): 211-216.

• 科技进展 • 上一篇    下一篇

奇特的小行星——灶神星

胡中为   

  1. 教授,南京大学天文学与空间科学学院,南京 210008
  • 出版日期:2013-06-25 发布日期:2013-08-19

Strange asteroid—Vesta

HU Zhong-wei   

  1. Professor, School of Astronomy and Space Science, Nanjing University, Nanjing 210008, China
  • Online:2013-06-25 Published:2013-08-19

摘要: 灶神星(Vesta)是小行星主带的最大成员之一。主带的最大成员——谷神星(Ceres)已归类为矮行星,灶神星也是候选的矮行星。不同于其他类型的小行星,灶神星是很奇特的。灶神星的光谱跟HED 陨石相似,因而推断它是该群陨石的母体。在灶神星族小行星和V 型小行星中,其他小行星都很小,可认为它们是灶神星受撞击而抛出的碎块。跟含水的谷神星不同,灶神星是缺水的火成岩石星,因此,它们倍受关注。为揭示谷神星和灶神星的奥秘,美国专门发射黎明号(Dawn)飞船去探测它们,现在已完成了环绕灶神星一年多的探测,正在飞往谷神星途中。黎明号飞船所摄的灶神星图像令人大为震惊,其南极区有两个大陨击盆地,证实了它曾受到巨大撞击所抛出碎块成为有关的小行星和陨石,并且造成其赤道区的大沟槽。灶神星有相似于类地行星的核、幔、壳结构和早期演化史,可能是遗留的原行星(protoplanet),因而,对灶神星的研究将有助于了解类地行星的起源和早期演化等问题。

关键词: 灶神星, 小行星, 黎明号飞船, HED 陨石, 矮行星, 原行星

Abstract: Vesta is one of the largest asteroids in the asteroids belt. The largest one-Ceres was classified as a dwarf planet. Vesta also is one of the candidates of dwarf planets. Different from other types of asteroids, Vesta is very strange. Vesta spectrum is similar with HED meteorite, so that it is thought to be the parent body of this meteorite group. In the Vesta family and V-type of asteroids, others are small,and they are inferred as fragments from impacted Vesta. Different from Ceres with H2O, Vesta is a dry igneous rock. Therefore, they are specially concerned. To reveal the mystery of Vesta and Ceres , special emission of Dawn spacecraft is to explore them. Dawn has detected around Vesta for more than a year, and is in the way to Ceres. The images of Vesta from Dawn are
surprising. Two large impact craters near its south pole confirmed that fragments from impacted Vesta become relevant asteroids and meteorites, which cause large trouphs in its equatorial region. The Vesta structure of core, mantle and crust,as well as its history of formation and early evolution are like terrestrial planet, which is helpful to research the origin and early evolution of terrestrial planets.

Key words: Vesta, asteroid, Dawn spacecraft, HED meteorite, dwarf planet, protoplanet