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The Process of Tholin Formation in Titan’s Upper Atmosphere
Coates, A. J.; Young, D. T.; Waite, J. H. +4 more
Titan’s lower atmosphere has long been known to harbor organic aerosols (tholins) presumed to have been formed from simple molecules, such as methane and nitrogen (CH4 and N2). Up to now, it has been assumed that tholins were formed at altitudes of several hundred kilometers by processes as yet unobserved. Using measurements …
The Variable Rotation Period of the Inner Region of Saturn’s Plasma Disk
Gurnett, D. A.; Persoon, A. M.; Dougherty, M. K. +4 more
We show that the plasma and magnetic fields in the inner region of Saturn’s plasma disk rotate in synchronism with the time-variable modulation period of Saturn’s kilometric radio emission. This relation suggests that the radio modulation has its origins in the inner region of the plasma disk, most likely from a centrifugally driven convective ins…
Saturn’s Gravitational Field, Internal Rotation, and Interior Structure
Anderson, John D.; Schubert, Gerald
Saturn’s internal rotation period is unknown, though it must be less than 10 hours, 39 minutes, and 22 seconds, as derived from magnetic field plus kilometric radiation data. By using the Cassini spacecraft’s gravitational data, along with Pioneer and Voyager radio occultation and wind data, we obtain a rotation period of 10 hours, 32 minutes, and…
Saturn’s Small Inner Satellites: Clues to Their Origins
Porco, C. C.; Thomas, P. C.; Weiss, J. W. +1 more
Cassini images of Saturn’s small inner satellites (radii of less than ~100 kilometers) have yielded their sizes, shapes, and in some cases, topographies and mean densities. This information and numerical N-body simulations of accretionary growth have provided clues to their internal structures and origins. The innermost ring-region satellites have…
Enceladus: Cosmic Graffiti Artist Caught in the Act
Verbiscer, Anne; Helfenstein, Paul; Showalter, Mark +1 more
As one of the most geologically active bodies in the solar system, Saturn's moon Enceladus not only coats itself with water ice particles, it accounts for the unusually high albedos of the other satellites orbiting within Saturn's vast, tenuous E ring. This effect is evident in Hubble Space Telescope observations obtained at true opposition on 13 …
The Source of Saturn’s G Ring
Porco, Carolyn C.; Hedman, Matthew M.; Burns, Joseph A. +6 more
The origin of Saturn’s narrow G ring has been unclear. We show that it contains a bright arc located 167,495.6 ± 1.3 km from Saturn’s center. This longitudinally localized material is trapped in a 7:6 corotation eccentricity resonance with the satellite Mimas. The cameras aboard the Cassini spacecraft mainly observe small (1 to 10 micrometers) dus…