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Fundamental parameters of He-weak and He-strong stars
Frémat, Y.; Zorec, J.; Arias, M. L. +3 more
Context: He-weak and He-strong stars are chemically peculiar AB objects whose He lines are anomalously weak or strong for their MK spectral type. The determination of fundamental parameters for these stars is often more complex than for normal stars due to their abundance anomalies.
Aims: We discuss the determination of fundamental parameters:…
Chorus source properties that produce time shifts and frequency range differences observed on different Cluster spacecraft
Gurnett, D. A.; Pickett, J. S.; SantolíK, O. +3 more
We present an explanation of frequency range differences and time shifts between corresponding chorus elements of whistler mode chorus which have been recently observed on multiple Cluster spacecraft. We show that a nonmoving or quasi-static source that emits waves in a relatively narrow interval of wave normal angles and that varies both the wave…
NACO-SDI Direct Imaging Search for the Exoplanet ɛ Eri b
Henning, Thomas; Reffert, Sabine; Brandner, Wolfgang +13 more
The active K2 V star ɛ Eri hosts the nearest known extrasolar planet. With an angular separation of about 1" on average, and an age of a few to several hundred megayears, ɛ Eri b is one of the prime candidates for becoming the first definitive extrasolar planet imaged directly. We present a multiepoch deep differential imaging survey performed wit…
A longer XMM-Newton look at IZwicky1: physical conditions and variability of the ionized absorbers
Brandt, W. N.; Costantini, E.; Fabian, A. C. +2 more
We present a spectral analysis of the narrow-line Seyfert 1 galaxy IZwicky1, focusing on the characteristics of the ionized absorbers as observed with XMM-Newton in 2005. The soft X-ray spectrum shows absorption by two components of ionized gas with a similar column density (NH ~ 1021cm-2) and ionization parameters…
Geochemistry of Venus' Surface: Current limitations as future opportunities
Treiman, Allan H.
Geochemical data about Venus' surface materials are quite limited and of poor precision. The Venera and VEGA lander missions (sources of the available data) were engineering and scientific triumphs, but their chemical analyses of the Venus surface do not permit detailed confident interpretation, such as are routine for terrestrial analyses and MER…
Descent motions of the Huygens probe as measured by the Surface Science Package (SSP): Turbulent evidence for a cloud layer
Zarnecki, John C.; Lorenz, Ralph D.; Leese, Mark R. +5 more
The Huygens probe underwent vigorous short-period motions during its parachute descent through the atmosphere of Saturn's moon Titan in January 2005, at least some of which were excited by the Titan environment. Several sensors in the Huygens Surface Science Package (SSP) detect these motions, indicating the transition to the smaller stabilizer pa…
Coherent whistler emissions in the magnetosphere - Cluster observations
Balogh, A.; Dandouras, I.; Lucek, E. +11 more
The STAFF-SC observations complemented by the data from other instruments on Cluster spacecraft were used to study the main properties of magnetospheric lion roars: sporadic bursts of whistler emissions at f~0.1-0.2fe where fe is the electron gyrofrequency. Magnetospheric lion roars are shown to be similar to the emissions in…
Low-power radio galaxy environments in the Subaru?/XMM-Newton Deep Field at z ~ 0.5
Read, A. M.; Rawlings, S.; Geach, J. E. +2 more
We present multiobject spectroscopy of galaxies in the immediate (Mpc-scale) environments of four low-power (L1.4GHz <~ 1025 WHz-1) radio galaxies at z ~ 0.5, selected from the Subaru?/XMM-Newton Deep Field. We use the spectra to calculate velocity dispersions and central redshifts of the groups the radio galaxi…
The magnetic field topology associated with two M flares
Mandrini, C. H.; Démoulin, P.; Luoni, M. L. +1 more
On 27 October, 2003, two GOES M-class flares occurred in an interval of 3 h in active region NOAA 10486. The two flares were confined and their associated brightenings appeared at the same location, displaying a very similar shape both at the chromospheric and coronal levels. We focus on the analysis of magnetic field (SOHO/MDI), chromospheric (HA…
Sensitivity of low degree oscillations to the change in solar abundances
Provost, J.; Berthomieu, G.; Morel, P. +2 more
Context: The most recent determination of the solar chemical composition, using a time-dependent, 3D hydrodynamical model of the solar atmosphere, exhibits a significant decrease of C, N, O abundances compared to their previous values. Solar models that use these new abundances are not consistent with helioseismological determinations of the sound…