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Recent Results from Titan's Ionosphere

Coates, A. J.; Wahlund, J. -E.; Szego, K. +4 more

Titan has the most significant atmosphere of any moon in the solar system, with a pressure at the surface larger than the Earth's. It also has a significant ionosphere, which is usually immersed in Saturn's magnetosphere. Occasionally it exits into Saturn's magnetosheath. In this paper we review several recent advances in our understanding of Tita…

Rotation-rate variations at the tachocline: An update

Thompson, M. J.; Howe, R.; Komm, R. +5 more

After 15 years of GONG and MDI observations of the solar interior rotation, we revisit the issue of variations in the rotation rate near the base of the convection zone. The 1.3-year period seen in the first few years of the observations disappeared after 2000 and has still not returned. On the other hand, the agreement between GONG and MDI observ…

Influence of heavy ionospheric ions on substorm onset

Winglee, R. M.; Harnett, E.

Multifluid/multiscale simulations are used to examine the influence of ionospheric outflows on two substorms that occurred on August 13, 2001. Both substorms had well defined onsets in Cluster ion spectrometer (CIS) data of ion composition of the plasma sheet. It is shown that the model is able to account for two orders of magnitude variation in t…

Energy-Dependent Timing of Thermal Emission in Solar Flares

Awasthi, Arun Kumar; Aschwanden, Markus J.; Jain, Rajmal +1 more

We report solar flare plasma to be multi-thermal in nature based on the theoretical model and study of the energy-dependent timing of thermal emission in ten M-class flares. We employ high-resolution X-ray spectra observed by the Si detector of the "Solar X-ray Spectrometer" (SOXS). The SOXS onboard the Indian GSAT-2 spacecraft was launched by the…

Unusually strong magnetic fields in Titan's ionosphere: T42 case study

Coates, A. J.; Russell, C. T.; Wei, H. Y. +7 more

Observations of unusually large magnetic fields in the ionosphere indicate periods of maximum stress on Titan's ionosphere and potentially of the strongest loss rates of ionospheric plasma. During Titan flyby T42, the observed magnetic field attained a maximum value of 37 nT between an altitude of 1200 and 1600 km, about 20 nT stronger than on any…

High-resolution Spectroscopy and Spectropolarimetry of Some Late F- / Early G-type Sun-like Stars as Targets for Zeeman Doppler Imaging

Hart, R.; Burton, D.; Marsden, S. C. +4 more

High-resolution spectroscopy and spectropolarimetry have been undertaken at the Anglo-Australian Telescope in order to identify suitable targets for magnetic studies of young Sun-like stars, for the proxy study of early solar evolution. This study involved the investigation of some variable late F- / early G-type Sun-like stars originally identifi…

Variable jets with non-top hat ejection cross sections: a model for the knots of the HH 34 jet

Raga, A. C.; Noriega-Crespo, A.; Esquivel, A. +3 more

We compute axisymmetric, single-sinusoidal mode variable ejection models with a non-top hat ejection velocity cross section. We find that for decreasing edge-to-center velocity ratios one obtains internal working surfaces with progressively more extended bow shock wings. These wings produce [S II] emission which partially fills in the inter-knot r…

Periodicity analysis of Jovian quasi-periodic radio bursts based on Lomb-Scargle periodograms

Morioka, Akira; Tsuchiya, Fuminori; Misawa, Hiroaki +3 more

The Jovian polar magnetosphere has relativistic particle accelerations with quasi-periodicity (hereafter QP accelerations) that are accompanied by periodic auroral emissions and low-frequency radio bursts called quasi-periodic (QP) bursts. Some previous observations suggested a possible physical relationship between the QP accelerations and QP rad…

Periglacial geomorphology and landscape evolution of the Tempe Terra region, Mars

Neukum, G.; Hauber, E.; Orosei, R. +3 more

Photometric observations of asteroid 4 Vesta by the OSIRIS cameras onboard the Rosetta spacecraft

Sierks, H.; Mottola, S.; Barucci, M. A. +2 more

Aims: We report on new observations of asteroid 4 Vesta obtained on 1 May 2010 with the optical system OSIRIS onboard the ESA Rosetta mission. One lightcurve was taken at a phase angle (52°) larger than achievable from ground-based observations together with a spectrophotometric sequence covering the 260 to 990 nm wavelength range.
Metho…