Search Publications
A deep search for Martian dust rings and inner moons using the Hubble Space Telescope
Nicholson, Philip D.; Hamilton, Douglas P.; Showalter, Mark R.
It has long been suspected that Mars might be encircled by two faint rings, one originating from each of its moons Phobos and Deimos. Meteoroid impacts into these moons should release clouds of dust that quickly spread out to become rings; similar dust rings have been associated with several small inner moons of the gas giants. On May 28, 2001 Mar…
To the depths of Venus: Exploring the deep atmosphere and surface of our sister world with Venus Express
Drossart, Pierre; Baines, Kevin H.; Piccioni, Giuseppe +6 more
With its comprehensive suite of near-infrared instruments, Venus Express will perform the first detailed global exploration of the depths of the thick Venusian atmosphere. Through the near-daily acquisition of Visible and Infrared maps and spectra, three infrared-sensing instruments - the Planetary Fourier Spectrometer (PFS), the Venus Monitoring …
Comet 67P/Churyumov Gerasimenko: Modeling of orientation and structure
Kossacki, Konrad J.; Szutowicz, Sławomira
The comet 67P/Churyumov-Gerasimenko is the current target of the mission Rosetta, initially planned to investigate comet 46P/Wirtanen. These two comets have similar orbits, except the distance to the Sun at perihelion, but different orbital histories and different masses. Thus, structures of the nuclei can be significantly different. The evolution…
Evidence for an Hesperian-aged South Circum-Polar Lake Margin Environment on Mars
Head, James W.; Dickson, James
A broad pitted plain and an elongated low rise occur near the south pole of Mars between a region of major cavi (Cavi Angusti) and a regionally smooth and broad valley (Argentea Planum). Viking, Mars Global Surveyor (MGS), and Odyssey data reveal a densely pitted plain covering ∼6750 km 2, and containing >300 irregularly shaped, stee…
Titan: Preliminary results on surface properties and photometry from VIMS observations of the early flybys
Sotin, C.; Brown, R. H.; Baines, K. H. +10 more
Cassini observations of the surface of Titan offer unprecedented views of its surface through atmospheric windows in the 1-5 µm region. Images obtained in windows for which the haze opacity is low can be used to derive quantitative photometric parameters such as albedo and albedo distribution, and physical properties such as roughness and pa…
Vertical pressure profile of Titan—observations of the PPI/HASI instrument
Harri, Ari-Matti; Mäkinen, Teemu; Siili, Tero +2 more
The Huygens entry probe descended through the atmosphere of Titan and provided an excellent set of observations of the atmosphere and the surface of Titan. During the 150-min descent the Huygens Atmospheric Structure Instrument (HASI) observed a comprehensive set of variables, including pressure, temperature, density and atmospheric electricity. T…
The planetary fourier spectrometer (PFS) onboard the European Venus Express mission
Baines, K. H.; Grigoriev, A.; Bellucci, G. +47 more
The planetary fourier spectrometer (PFS) for the Venus Express mission is an infrared spectrometer optimized for atmospheric studies. This instrument has a short wavelength (SW) channel that covers the spectral range from 1700 to 11400 cm -1 (0.9-5.5 µm) and a long wavelength (LW) channel that covers 250-1700 cm -1 (5.5…
GCM simulation of balloon trajectories on Titan
Lorenz, Ralph D.; Tokano, Tetsuya
Possible trajectories of passive balloons in Titan's troposphere are simulated with the instantaneous wind field predicted by a GCM (general circulation model). In most areas the basic motion of a balloon is a predominantly eastward or westward drift, depending on altitude, latitude and season of the balloon release point. Some meridional oscillat…
Outstanding aeronomy problems at Venus
Witasse, O.; Nagy, A. F.
Of all the non-terrestrial ionospheres and thermospheres in our solar system those of Venus have been explored and studied the most. This is mainly because of the 14 year exploration of the well-instrumented Pioneer Venus spacecraft and the theoretical studies prompted by the resulting observational information. However, there are still a number o…
Chaotic gravitational zones around a regularly shaped complex rotating body
Mysen, E.; Aksnes, K.; Olsen, Ø.
In preparation for the Rosetta mission, the location and widths of gravitational resonances surrounding a regularly shaped and possibly complex rotating body are mapped following the second fundamental model of resonance. It is found that for uniaxial rotation of the central body, the surrounding resonances are widest for prograde orbits. If the f…