2011年09月19日:灶神星的南端-（The South Pole of Asteroid Vesta）

2011年09月19日:灶神星的南端-（The South Pole of Asteroid Vesta）--原图下载

Image Credit: NASA, JPL-Caltech, UCLA, MPS, DLR, IDA
说明: 灶神星南端的环型结构是怎么产生的？上个月，黎明号太空船抵达小行星带，成为首颗绕行这个排名第二小行星的太空船。这张影像解析度高达260公尺，灶神星上的丘陵、陨石坑、还有断崖都清晰可见，还有其他分布在这颗直径500公里小行星右下方的表面陨石坑上，粗糙环形特徵都是清清楚楚。先前研究指出，这样的特徵是因为碰撞合併了一颗较小的小行星。其他的可能则为，这些特徵可能就在小行星形成后不久，由于内部过程而产生的。随着黎明号太空船持续地螺旋靠近这颗小行星，未来几个月将会纪录下更高解析度的影像，可能会提供新的线索。

原文：

Image Credit: NASA, JPL-Caltech, UCLA, MPS, DLR, IDA
Explanation: What created the circular structure around the south pole of asteroid Vesta?Pictured above, the bottom of the second largest object in the asteroid belt was recently imaged for the first time by the robotic Dawn satellite that arrived last month.A close inspection of the 260-meter resolution image shows not only hills and craters and cliffs and more craters, but ragged circular features that cover most of the lower right of the 500-kilometer sized object.Early speculation posits that the structure might have been created by a collision and coalescence with a smaller asteroid.Alternatively, the features might have originated in an internal process soon after the asteroid formed.New clues might come in the next few months as Dawn spirals down toward the rocky world and obtains images of increasingly high resolution.