Search Publications
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 …
Collisional evolution of the asteroid belt
Cheng, Andrew F.
A new synthesis of asteroid collisional evolution is motivated by the question of whether most asteroids larger than ∼1 km size are strengthless gravitational aggregates (rubble piles). NEAR found Eros not to be a rubble pile, but a shattered collisional fragment, with a through-going fracture system, and an average of about 20 m regolith cover. O…
Saturn's cloud morphology and zonal winds before the Cassini encounter
Hueso, R.; Sánchez-Lavega, A.; Rojas, J. F. +2 more
Analyses of Hubble Space Telescope (HST) images of Saturn obtained from August 2003 to March 2004, with extensive support from ground-based telescopes, have been used to characterize the cloud morphology and motions in its atmosphere few months before the Cassini encounter. We present data on the major meteorological features as potential targets …
The jovian rings: new results derived from Cassini, Galileo, Voyager, and Earth-based observations
Nicholson, P. D.; Burns, J. A.; Showalter, M. R. +3 more
Cassini's Imaging Science Subsystem (ISS) instrument took nearly 1200 images of the Jupiter ring system during the spacecraft's 6-month encounter with Jupiter (Porco et al., 2003, Science 299, 1541-1547). These observations constitute the most complete data set of the ring taken by a single instrument, both in phase angle (0.5°-120° at seven angle…