Particle deposition on the saturnian satellites from ephemeral cryovolcanism on Enceladus
Particle deposition on the saturnian satellites from ephemeral cryovolcanism on Enceladus
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土星卫星上土星卫星上土卫二短暂冷冻火山作用的颗粒沉积
DOI：
10.1002/2014gl060470
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发表时间：
2014
影响因子：
5.2
通讯作者：
Adam Showman
中科院分区：
文献类型：
--
作者：
Naoyuki Hirata;Hideaki Miyamoto;Adam Showman
土卫二南极的地质活动产生了微米大小的粒子羽流，这些粒子可能形成了土星从土卫一轨道延伸到土卫六的脆弱E环。这些粒子和卫星之间的相互作用已经被提出，尽管只是非常薄的表面现象。我们用新开发的Helene数值形状模型仔细检查了高分辨率图像，发现Helene的前半球被厚厚的E环颗粒沉积物覆盖，这些颗粒偶尔会坍塌形成沟壑状凹陷。由此产生的沟壑的深度和几乎没有小陨石坑的领导半球表明，存款是几十到几百米厚。沉积物的年龄小于几十年My，这与Telesto和Calypso上发现的类似沉积物相吻合。我们的发现以及以前的理论工作共同表明，目前在土卫二上发生的冰火山活动是短暂的。
The geologically active south pole of Enceladus generates a plume of micron‐sized particles, which likely form Saturn's tenuous E‐ring extending from the orbit of Mimas to Titan. Interactions between these particles and satellites have been suggested, though only as very thin surficial phenomena. We scrutinize high‐resolution images with a newly developed numerical shape model of Helene and find that the leading hemisphere of Helene is covered by thick deposits of E‐ring particles, which occasionally collapse to form gully‐like depressions. The depths of the resultant gullies and near‐absence of small craters on the leading hemisphere indicate that the deposit is tens to hundreds of meters thick. The ages of the deposits are less than several tens of My, which coincides well with similar deposits found on Telesto and Calypso. Our findings as well as previous theoretical work collectively indicate that the cryovolcanic activity currently occurring on Enceladus is ephemeral.