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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 lakes of Titan
Lorenz, R. D.; Stiles, B.; Kelleher, K. +35 more
The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive…
The composition of Titan's stratosphere from Cassini/CIRS mid-infrared spectra
Bézard, Bruno; Vinatier, Sandrine; Lellouch, Emmanuel +22 more
We have analyzed data recorded by the Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft during the Titan flybys T0-T10 (July 2004-January 2006). The spectra characterize various regions on Titan from 70° S to 70° N with a variety of emission angles. We study the molecular signatures observed in the mid-infrared CIRS detector arr…
Discovery of heavy negative ions in Titan's ionosphere
Lewis, G. R.; Coates, A. J.; Sittler, E. C. +3 more
Titan's ionosphere contains a rich positive ion population including organic molecules. Here, using CAPS electron spectrometer data from sixteen Titan encounters, we reveal the existence of negative ions. These ions, with densities up to ~100 cm-3, are in mass groups of 10-30, 30-50, 50-80, 80-110, 110-200 and 200+ amu/charge. During on…
Ion chemistry and N-containing molecules in Titan's upper atmosphere
Yelle, R. V.; Vuitton, V.; McEwan, M. J.
High-energy photons, electrons, and ions initiate ion-neutral chemistry in Titan's upper atmosphere by ionizing the major neutral species (nitrogen and methane). The Ion and Neutral Mass Spectrometer (INMS) onboard the Cassini spacecraft performed the first composition measurements of Titan's ionosphere. INMS revealed that Titan has the most compo…
Shear heating as the origin of the plumes and heat flux on Enceladus
Spencer, J. R.; Nimmo, F.; Pappalardo, R. T. +1 more
Enceladus, a small icy satellite of Saturn, has active plumes jetting from localized fractures (`tiger stripes') within an area of high heat flux near the south pole. The plume characteristics and local high heat flux have been ascribed either to the presence of liquid water within a few tens of metres of the surface, or the decomposition of clath…
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…
Cryovolcanic features on Titan's surface as revealed by the Cassini Titan Radar Mapper
Soderblom, L. A.; Ostro, S. J.; West, R. D. +41 more
The Cassini Titan Radar Mapper obtained Synthetic Aperture Radar images of Titan's surface during four fly-bys during the mission's first year. These images show that Titan's surface is very complex geologically, showing evidence of major planetary geologic processes, including cryovolcanism. This paper discusses the variety of cryovolcanic featur…
The dynamics of Jupiter and Saturn in the gaseous protoplanetary disk
Morbidelli, Alessandro; Crida, Aurélien
We study the possibility that the mutual interactions between Jupiter and Saturn prevented Type II migration from driving these planets much closer to the Sun. Our work extends previous results by Masset and Snellgrove [Masset, F., Snellgrove, M., 2001. Mon. Not. R. Astron. Soc. 320, L55-L59], by exploring a wider set of initial conditions and dis…
Vertical abundance profiles of hydrocarbons in Titan's atmosphere at 15° S and 80° N retrieved from Cassini/CIRS spectra
Bézard, Bruno; Vinatier, Sandrine; Nixon, Conor A. +8 more
Limb spectra recorded by the Composite InfraRed Spectrometer (CIRS) on Cassini provide information on abundance vertical profiles of C 2H 2, C 2H 4, C 2H 6, CH 3C 2H, C 3H 8, C 4H 2, C 6H 6 and H…