Shell thickness variations and the long-wavelength topography of Titan
Shell thickness variations and the long-wavelength topography of Titan
复制标题
泰坦的壳厚度变化和长波长地形
DOI：
10.1016/j.icarus.2010.02.020
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发表时间：
2010
期刊：
影响因子：
3.2
通讯作者：
B. Bills
中科院分区：
文献类型：
--
作者：
F. Nimmo;B. Bills
土卫六的长波长地形的振幅比它目前距离土星的潮汐和旋转扭曲所预期的要大。这种地形与小的重力异常有关，表明补偿程度很高。这两个观测结果都可以解释，如果土卫六有一个浮动的，均衡补偿的冰壳与空间变化的厚度。空间变化的出现，因为横向变化的潮汐加热内的冰壳。模型结合壳厚度的变化，结果在一个改进的适合的意见和度2潮汐勒夫数h2t符合预期，而不需要土卫六已经远离土星。我们的首选模型有一个平均壳厚为100公里，与观测到的重力异常一致，和一个适合于南极泰坦的热通量。壳层厚度的变化被对流消除，因此我们得出结论，泰坦的冰壳在今天没有对流。
The long-wavelength topography of Titan has an amplitude larger than that expected from tidal and rotational distortions at its current distance from Saturn. This topography is associated with small gravity anomalies, indicating a high degree of compensation. Both observations can be explained if Titan has a floating, isostatically-compensated ice shell with a spatially-varying thickness. The spatial variations arise because of laterally-variable tidal heating within the ice shell. Models incorporating shell thickness variations result in an improved fit to the observations and a degree-two tidal Love number h2tconsistent with expectations, without requiring Titan to have moved away from Saturn. Our preferred models have a mean shell thickness of ≈100km in agreement with the observed gravity anomalies, and a heat flux appropriate to a chondritic Titan. Shell thickness variations are eliminated by convection; we therefore conclude that Titan’s ice shell is not convecting at the present day.