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Comparative planetology, climatology and biology of Venus, Earth and Mars
Taylor, F. W.
Spacecraft studies of the three terrestrial planets with atmospheres have made it possible to make meaningful comparisons that shed light on their common origin and divergent evolutionary paths. Early in their histories, all three apparently had oceans and extensive volcanism; Mars and Earth, at least, had magnetic fields, and Earth, at least, had…
Observations of an auroral streamer in a double oval configuration
Owen, C. J.; Nakamura, R.; Takada, T. +5 more
During the late evening and night of 14 September 2004, the nightside auroral oval shows a distinct double oval configuration for several hours after a substorm onset at ~18:45 UT. This structure is observed both by the IMAGE satellite optical instruments focusing on the Southern Hemisphere, and by the MIRACLE ground-based instrument network in Sc…
General X-ray properties of hot, massive stars
Nazé, Yaël
The recent X-ray observatories have not yet provided a large survey comparable (in sky coverage) to that based upon the ROSAT All-Sky Survey (RASS). However, two limited surveys exist : the 2XMM catalog for XMM-Newton (294 OB stars detected) and the Carina large-scale survey from Chandra (129 OB stars detected). Medium-resolution (CCD) spectra wer…
Ionization structure and Fe Kα energy for irradiated accretion discs
Zhao, Y. H.; Soria, R.; Zhou, X. L.
We study the radial ionization structure at the surface of an X-ray illuminated accretion disc. We plot the expected iron Kα line energy as a function of the Eddington ratio and of the distance of the emitting matter from the central source, for a non-rotating and a maximally rotating black hole. We compare the predicted disc line energies with th…
Reference frame and time standard used in INTEGRAL/OMC datasets
Domingo, Albert; Zejda, Miloslav
Short description of time coordinate used in INTEGRAL/OMC data is given. The variable-star community uses observations from the INTEGRAL/OMC satellite, but it seems that with incorrect interpretation of time given there.
Space charge effects and arc properties of simulated lightning on Venus
Robledo-Martinez, A.; Sobral, H.; Ruiz-Meza, A.
An experimental investigation of the physical properties of lightning on Venus was carried out by applying fast impulses to a pressurized (1-2.8 atm) CO2-N2 gas mix. The maximum current employed in the experiments was 2.8 kA. It was found that the pressure has a marked effect on the measured electric field. This effect is mos…
Modelling of spacecraft spin period during eclipse
Frey, H. U.; Plaschke, F.; Georgescu, E. +2 more
The majority of scientific satellites investigating the Earth magnetosphere are spin stabilized. The attitude information comes usually from a sun sensor and is missing in the umbra; hence, the accurate experimental determination of vector quantities is not possible during eclipses. The spin period of the spacecraft is generally not constant durin…
Observations of electron vorticity in the inner plasma sheet
Fazakerley, A. N.; Gurgiolo, C.; Goldstein, M. L. +2 more
From a limited number of observations it appears that vorticity is a common feature in the inner plasma sheet. With the four Cluster spacecraft and the four PEACE instruments positioned in a tetrahedral configuration, for the first time it is possible to directly estimate the electron fluid vorticity in a space plasma. We show examples of electron…
Tracking a Ulysses High-latitude ICME Event Back to Its Solar Origins
Dumitrache, C.; Popescu, N. A.; Oncica, A.
High-latitude interplanetary mass ejections (ICMEs) observed beyond 1 AU are not studied very often. They are useful for improving our understanding of the 3D heliosphere. As there are only few such events registered by the Ulysses spacecraft, the task of detecting their solar counterparts is a challenge, especially during high solar activity peri…
The abundance of iron-peak elements and the dust composition in η Carinae: manganese
Gull, T. R.; Bautista, M. A.; Hartman, H. +2 more
We study the chemical abundances of the strontium filament found in the ejecta of η Carinae. In particular, we derive the abundances of iron-peak elements from the spectra of their singly ionized ions present in the optical/infrared (IR) spectra. In this paper we analyse the spectrum of Mn II using a new non-local thermodynamic equilibrium (non-LT…