Saturn from HST

Saturn from Voyager a 9.5 AU P 29.5 yr i (orb) 2.5o e 0.056 Prot 0.43 d i (rot) 27o R 9.5 RE M 95 ME r 0.69 g/cc g 1 gE vesc 36 km/s A 0.46

Oblateness of Saturn

Saturn Highlights Magnetic field about 2/3 of Earth’s Atmosphere and interior structure similar to Jupiter Yellowish-tan clouds and fewer dynamic storms Rings are splendoriforous!

Saturn’s Magnetosphere

Multi-Wavelength Saturn

Saturnian Atmosphere

Interior of Saturn

Internal Heat of Saturn Sat. receives on 25% as much sunlight as Jup. Yet, Sat. emits 50% more than what it absorbs! Similar to Jup., but for same reason? No! Heat from gravitational contraction should now be gone, since Sat. is smaller Instead, He may be draining thru metallic H mantle to the core, thereby liberating heat In hotter Jup., He remains dissolved – no draining Consequence: He depleted in Sat. atm. – explains why He/H = 1/4 for Jup. but 1/7 for Sat.

Artsy “Ring World” 1610: Galileo first observed the rings of Saturn, but not clearly; appeared more like appendages (sorta like a triple planet) 1660’s: Rings clearly seen to encircle the planet; ring gaps discovered (Cassini’s division, Encke’s division) 1859: Maxwell shows that the rings cannot be solid 1895: Keeler confirms Maxwell with measurements

The Rings of Saturn Rings are 200,000 km across, but less than 0.2 km thick! Consist mostly of icy particles, ranging in size from 1 cm to 10 m Rings reside inside the Roche Limit Main features: Gaps Sharp edges Spokes Shepherding satellites

Saturn’s Rings

Enceladus Above the Rings

Spokes on the Rings

Scale Model of Saturnian System

Rings of the Gas Giants