The Cassini mission has provided measurements of the gravity of several moons of Saturn as well as an estimate of the tidal response, which is expressed as the degree 2 Love number k₂ of its largest moon, Titan. The first estimates of Titan’s Love number were larger than pre-Cassini expectations. Interior modelling suggested it may be explained with a dense ocean, but the interpretation remains unclear. We analysed Cassini tracking data to determine Titan’s gravity field and its Love number. Our gravity results are consistent with earlier studies, but we find a lower Love number for Titan of k₂ = 0.375 ± 0.06. This lower value follows from an elaborate investigation of the tidal effects. We show that a dense ocean is not implied by the obtained Love number; instead, a water or ammonia ocean is more probable. A lower density ocean can increase the likeliness of contact between the silicate core and ocean, which can leach minerals into the ocean and could promote its habitability.

卡西尼号任务提供了土星几颗卫星的重力测量值以及潮汐响应的估计值，潮汐响应以土星最大卫星土卫六的度数 2 Love 数k ₂表示。对泰坦爱号的初步估计比卡西尼号之前的预期要大。内部模型表明，这可能是用稠密的海洋来解释的，但解释仍不清楚。我们分析了卡西尼号跟踪数据以确定土卫六的重力场及其洛夫数。我们的重力结果与早期的研究一致，但我们发现泰坦的洛夫数较低，为k ₂  = 0.375 ± 0.06。这个较低的值是根据对潮汐效应的详细研究得出的。我们表明，所获得的洛夫数并不暗示稠密的海洋；相反，水或氨海洋的可能性更大。较低密度的海洋可以增加硅酸盐核心与海洋之间接触的可能性，从而可以将矿物质浸入海洋并促进其宜居性。