Secondary Cratering From Rheasilvia as the Possible Origin of Vesta's Equatorial Troughs
Secondary Cratering From Rheasilvia as the Possible Origin of Vesta's Equatorial Troughs
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DOI：
10.1029/2022je007473
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发表时间：
2023-03
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影响因子：
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通讯作者：
N. Hirata
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作者：
N. Hirata
灶神星有一组平行的槽与它的赤道对齐。虽然以往的评价认为它是冲击破裂构造成因，但我们认为赤道海槽可能是由最大的撞击盆地Rheasilvia的二次撞击形成的。考虑到灶神星的快速旋转，我们计算了来自雷亚西尔维亚的喷射粒子的轨迹。因此，我们发现次级陨石坑应该与纬度平行。特别是，如果我们假设喷射粒子以大约350-380 m/s的初始发射速度和25°的发射角度发射，平行的赤道槽Divalia Fossae可以用次级陨石坑来解释。这个模型适用于妊神星、萨拉西亚星和查里克罗星等天体，但不适用于水星、月球和常规卫星。
Asteroid 4 Vesta has a set of parallel troughs aligned with its equator. Although previous evaluations suggest that it is of shock fracturing tectonic origin, we propose that the equatorial troughs can be created by secondary cratering from the largest impact basin, Rheasilvia. We calculated the trajectories of ejecta particles from Rheasilvia by considering Vesta's rapid rotation. As a result, we found that secondary craters should be parallel to the latitude. In particular, if we assume that ejecta particles are launched at an initial launch velocity of approximately 350–380 m/s and a launch angle of 25°, the parallel equatorial troughs, the Divalia Fossae, can be suitably explained by secondary cratering. This model works well on objects, such as Haumea, Salacia, and Chariklo, but not on Mercury, the Moon, and regular satellites.