Search Publications
Images of Asteroid 21 Lutetia: A Remnant Planetesimal from the Early Solar System
Jorda, L.; Pätzold, M.; Bertaux, J. -L. +55 more
Images obtained by the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) cameras onboard the Rosetta spacecraft reveal that asteroid 21 Lutetia has a complex geology and one of the highest asteroid densities measured so far, 3.4 ± 0.3 grams per cubic centimeter. The north pole region is covered by a thick layer of regolith, which…
A Reservoir of Ionized Gas in the Galactic Halo to Sustain Star Formation in the Milky Way
Lehner, Nicolas; Howk, J. Christopher
Without a source of new gas, our Galaxy would exhaust its supply of gas through the formation of stars. Ionized gas clouds observed at high velocity may be a reservoir of such gas, but their distances are key for placing them in the galactic halo and unraveling their role. We have used the Hubble Space Telescope to blindly search for ionized high-…
The Surface Composition and Temperature of Asteroid 21 Lutetia As Observed by Rosetta/VIRTIS
Langevin, Y.; Bellucci, G.; Jaumann, R. +46 more
The Visible, InfraRed, and Thermal Imaging Spectrometer (VIRTIS) on Rosetta obtained hyperspectral images, spectral reflectance maps, and temperature maps of the asteroid 21 Lutetia. No absorption features, of either silicates or hydrated minerals, have been detected across the observed area in the spectral range from 0.4 to 3.5 micrometers. The s…
Evidence of Water Vapor in Excess of Saturation in the Atmosphere of Mars
Forget, F.; Maltagliati, L.; Montmessin, F. +3 more
The vertical distribution of water vapor is key to the study of Mars’ hydrological cycle. To date, it has been explored mainly through global climate models because of a lack of direct measurements. However, these models assume the absence of supersaturation in the atmosphere of Mars. Here, we report observations made using the SPICAM (Spectroscop…
Detection of Emerging Sunspot Regions in the Solar Interior
Zhao, Junwei; Ilonidis, Stathis; Kosovichev, Alexander
Sunspots are regions where strong magnetic fields emerge from the solar interior and where major eruptive events occur. These energetic events can cause power outages, interrupt telecommunication and navigation services, and pose hazards to astronauts. We detected subsurface signatures of emerging sunspot regions before they appeared on the solar …
Thermal Structure and Dynamics of Saturn’s Northern Springtime Disturbance
Nicholson, Philip D.; Fletcher, Leigh N.; Sotin, Christophe +16 more
Saturn’s slow seasonal evolution was disrupted in 2010-2011 by the eruption of a bright storm in its northern spring hemisphere. Thermal infrared spectroscopy showed that within a month, the resulting planetary-scale disturbance had generated intense perturbations of atmospheric temperatures, winds, and composition between 20° and 50°N over an ent…
Asteroid 21 Lutetia: Low Mass, High Density
Pätzold, M.; Lamy, P.; Sierks, H. +9 more
Asteroid 21 Lutetia was approached by the Rosetta spacecraft on 10 July 2010. The additional Doppler shift of the spacecraft radio signals imposed by 21 Lutetia’s gravitational perturbation on the flyby trajectory were used to determine the mass of the asteroid. Calibrating and correcting for all Doppler contributions not associated with Lutetia, …
Venus’s Southern Polar Vortex Reveals Precessing Circulation
Erard, S.; Drossart, P.; Piccioni, G. +5 more
Initial images of Venus’s south pole by the Venus Express mission have shown the presence of a bright, highly variable vortex, similar to that at the planet’s north pole. Using high-resolution infrared measurements of polar winds from the Venus Express Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument, we show the vortex to hav…
Saturn’s Curiously Corrugated C Ring
Hedman, M. M.; Burns, J. A.; Porco, C. C. +2 more
In August 2009 the Sun illuminated Saturn’s rings from almost exactly edge-on, revealing a subtle corrugation that extends across the entire C ring. This corrugation’s amplitude is 2 to 20 meters and its wavelength is 30 to 80 kilometers. Radial trends in the corrugation’s wavelength indicate that this structure—like a similar corrugation previous…
The Impact of Comet Shoemaker-Levy 9 Sends Ripples Through the Rings of Jupiter
Hedman, Matthew M.; Showalter, Mark R.; Burns, Joseph A.
Jupiter’s main ring shows vertical corrugations reminiscent of those recently detected in the rings of Saturn. The Galileo spacecraft imaged a pair of superimposed ripple patterns in 1996 and again in 2000. These patterns behave as two independent spirals, each winding up at a rate defined by Jupiter’s gravity field. The dominant pattern originate…