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Observations and temperatures of Io's Pele Patera from Cassini and Galileo spacecraft images
Turtle, Elizabeth P.; Radebaugh, Jani; McEwen, Alfred S. +4 more
Pele has been the most intense high-temperature hotspot on Io to be continuously active during the Galileo monitoring from 1996-2001. A suite of characteristics suggests that Pele is an active lava lake inside a volcanic depression. In 2000-2001, Pele was observed by two spacecraft, Cassini and Galileo. The Cassini observations revealed that Pele …
Search for spatial variation in the jovian 15N/ 14N ratio from Cassini/CIRS observations
Nixon, Conor A.; Irwin, Patrick G. J.; Fouchet, Thierry +4 more
We have used the spectra obtained by the Composite Infrared Spectrometer (CIRS) onboard the Cassini spacecraft to search for latitudinal variation in the 15N/ 14N ratio on Jupiter. We found no variations statistically significant given the observational and model uncertainties. The absence of latitudinal variations demonstrat…
Large impact features on middle-sized icy satellites
Schenk, Paul M.; McKinnon, William B.; Moore, Jeffrey M. +2 more
All of the large impact features of the middle-sized icy satellites of Saturn and Uranus that were clearly observed by the Voyager spacecraft are described. New image mosaics and stereo-and-photoclinometrically-derived digital elevation models are presented. Landforms related to large impact features, such as secondary craters and possible antipod…
Life cycles of spots on Jupiter from Cassini images
Porco, Carolyn C.; Ingersoll, Andrew P.; Ewald, Shawn P. +3 more
Using the sequence of 70-day continuum-band (751 nm) images from the Cassini Imaging Science System (ISS), we record over 500 compact oval spots and study their relation to the large-scale motions. The ∼100 spots whose vorticity could be measured—the large spots in most cases—were all anticyclonic. We exclude cyclonic features (chaotic regions) be…
Cassini between Earth and asteroid belt: first in-situ charge measurements of interplanetary grains
Kempf, S.; Krüger, H.; Srama, R. +9 more
Dust particles in interplanetary space are expected to charge up to an electrostatic potential of about +5 V mostly by the solar UV (Horányi, 1996, Annu. Rev. Astrophys. 34, 383). Since the dynamics of charged grains may be quite different from neutral particles, the knowledge of the grain charge Qd is highly desirable. In the last two …
Cassini observations of Io's visible aurorae
Geissler, Paul; McEwen, Alfred; Porco, Carolyn +4 more
More than 500 images of Io in eclipse were acquired by the Cassini spacecraft in late 2000 and early 2001 as it passed through the jovian system en route to Saturn (Porco et al., 2003, Science 299, 1541-1547). Io's bright equatorial glows were detected in Cassini's near-ultraviolet filters, supporting the interpretation that the visible emissions …
Ion winds in Saturn's southern auroral/polar region
Stallard, Tom S.; Miller, Steve; Geballe, Thomas R. +2 more
We present profiles of the line-of-sight (l.o.s.) ionospheric wind velocities in the southern auroral/polar region of Saturn. Our velocities are derived from the measurement of Doppler shifting of the H 3+ν2Q(1,0 -) line at 3.953 microns. The data for this study were obtained using the facility high-reso…
Lightning on Jupiter observed in the Hα line by the Cassini imaging science subsystem
West, Robert A.; Porco, Carolyn C.; Dyudina, Ulyana A. +4 more
Night side images of Jupiter taken by the Cassini Imaging Science Subsystem (ISS) camera with the H filter reveal four lightning clusters; two of them are repeated observations of the same storm. All of these flashes are associated with storm clouds seen a few hours earlier on the day side of Jupiter. Some of the clouds associated with lightning d…
A three-dimensional model of moist convection for the giant planets II: Saturn's water and ammonia moist convective storms
Hueso, Ricardo; Sánchez-Lavega, Agustín
Moist convective storms constitute a key aspect in the global energy budget of the atmospheres of the giant planets. Among them, Saturn is known to develop the largest scale convective storms in the Solar System, the Great White Spots (GWS) which occur rarely and have been detected once every 30 years approximately. On the average, Saturn seems to…
A tale of two very different comets: ISO and MSX measurements of dust emission from 126P/IRAS (1996) and 2P/Encke (1997)
A'Hearn, M. F.; Kostiuk, T.; Grün, E. +7 more
We present the characteristics of the dust comae of two comets, 126P/IRAS, a member of the Halley family (a near-isotropic comet), and 2P/Encke, an ecliptic comet. We have primarily used mid- and far-infrared data obtained by the ISOPHOT instrument aboard the Infrared Space Observatory (ISO) in 1996 and 1997, and mid-infrared data obtained by the …