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. Author manuscript; available in PMC: 2019 Apr 22.
Published in final edited form as: Astrophys J. 2017 Feb 13;836(1):109. doi: 10.3847/1538-4357/836/1/109

Table 1.

Some properties of Saturn’s mid-size moons.

Distance (Rℏ) Mass (10−6 Mℏ) Density (g cm−3) Rock mass fraction (%) Mass of rock (1019 kg)
Mimas 3.18 0.066 1.15 17 – 29 0.64 – 1.1
Enceladus 4.09 0.19 1.61 52 – 61 5.6 – 6.6
Tethys 5.06 1.09 0.97 0 – 6 0 – 3.7
Dione 6.47 1.93 1.48 42 – 52 46 – 57
Rhea 9.05 4.06 1.23 25 – 35 58 – 81

Note—Distance, mass, density, estimated mass of rock and rock mass fraction of Saturn’s mid-size moons. Mℏ = 568.46 × 1024 kg and Rℏ = 58 232 km are Saturn’s mass and mean radius. Mimas, Enceladus and Tethys all have ≤ 7 × 1019 kg in rock, while the outer two (Dione and Rhea) each have about an order-of-magnitude more. Enceladus’s density may have been lower in the past if it has lost substantial ice through geophysical activity.