Search Publications
Anomalously low solar extreme-ultraviolet irradiance and thermospheric density during solar minimum
Woods, Thomas N.; Didkovsky, Leonid V.; Solomon, Stanley C. +2 more
Solar activity during 2007-2009 was very low, and during this protracted solar minimum period, the terrestrial thermosphere was cooler and lower in density than expected. Measurements from instruments on the SOHO and TIMED spacecraft, and by suborbital rocket flights, indicate that solar extreme-ultraviolet irradiance levels were lower than they w…
Initial results for the north pole of the Moon from Mini-SAR, Chandrayaan-1 mission
Kirk, R. L.; Neish, C. D.; Butler, B. J. +27 more
We present new polarimetric radar data for the surface of the north pole of the Moon acquired with the Mini-SAR experiment onboard India's Chandrayaan-1 spacecraft. Between mid-February and mid-April, 2009, Mini-SAR mapped more than 95% of the areas polewards of 80° latitude at a resolution of 150 meters. The north polar region displays backscatte…
Cluster observations of EMIC triggered emissions in association with Pc1 waves near Earth's plasmapause
Pickett, J. S.; Dandouras, I.; Santolík, O. +8 more
The Cluster spacecraft were favorably positioned on the nightside near the equatorial plasmapause of Earth at L ∼ 4.3 on 30 March 2002 to observe electromagnetic ion cyclotron (EMIC) rising tone emissions in association with Pc1 waves at 1.5 Hz. The EMIC rising tone emissions were found to be left-hand, circularly polarized, dispersive, and propag…
First observation of a mini-magnetosphere above a lunar magnetic anomaly using energetic neutral atoms
Barabash, Stas; Holmström, Mats; Futaana, Yoshifumi +7 more
The Sub-keV Atom Reflecting Analyzer (SARA) instrument on the Indian Chandrayaan-1 spacecraft has produced for the first time an image of a lunar magnetic anomaly in backscattered hydrogen atoms. The image shows that a partial void of the solar wind, a mini-magnetosphere, is formed above the strong magnetic anomaly near the Crisium antipode. The m…
Pumping out the atmosphere of Mars through solar wind pressure pulses
Barabash, S.; Futaana, Y.; Fränz, M. +6 more
We study atmospheric escape from Mars during solar wind pressure pulses. During the solar minimum of 2007-08 we have observed 41 high pressure events, which are predominantly identified as corotating interaction regions (CIR) while a few are coronal mass ejections (CME), in data from the Advanced Composition Explorer (ACE) upstream of the Earth. 3…
Evolution of Titan's rocky core constrained by Cassini observations
Lunine, Jonathan I.; Castillo-Rogez, Julie C.
We model the thermal evolution of Titan's core and search for solutions that are consistent with the mean moment of inertia yielded by the Cassini-Huygens Mission. Like previous studies we assume that Titan's core is enriched in hydrated silicates. However, our modeling accounts for the possible dehydration of these minerals. The resulting models …
Properties of Saturn kilometric radiation measured within its source region
Schippers, P.; André, N.; Gurnett, D. A. +9 more
On 17 October 2008, the Cassini spacecraft crossed the southern sources of Saturn kilometric radiation (SKR), while flying along high-latitude nightside magnetic field lines. In situ measurements allowed us to characterize for the first time the source region of an extra-terrestrial auroral radio emission. Using radio, magnetic field and particle …
Saturn's internal planetary magnetic field
Russell, C. T.; Dougherty, M. K.; Burton, M. E.
A model of Saturn's internal planetary magnetic field based on data from the Cassini prime mission has been derived. In the absence of a determination of the rotation rate, the model is constrained to be axisymmetric. Non-axisymmetric models for a range of plausible planetary rotation periods have also been derived and we evaluate upper limits on …
Hemispheric asymmetry of the magnetic field wrapping pattern in the Venusian magnetotail
Kallio, E.; Luhmann, J. G.; Russell, C. T. +7 more
We examine statistically the magnetic field in the Venusian magnetotail which is formed by the draping of interplanetary magnetic field lines. Although the near-planet and distant magnetotail regions have been sampled by the various missions to Venus and the general magnetic features of the distant magnetotail are well established, the near wake r…
Near-tropical subsurface ice on Mars
Bibring, Jean-Pierre; Mustard, John; Forget, François +4 more
Near-surface perennial water ice on Mars has been previously inferred down to latitudes of about 45° and could result from either water vapor diffusion through the regolith under current conditions or previous ice ages precipitations. In this paper we show that at latitudes as low as 25° in the southern hemisphere buried water ice in the shallow (…