Search Publications
Properties of the Solar Acoustic Source Inferred from Nonadiabatic Oscillation Spectra
Kosovichev, A. G.; Wachter, R.
Severino et al. suggested in 2001 that observed power and cross spectra of medium-degree p-modes in velocity and intensity can be described by splitting the solar background noise into correlated, coherent, and uncoherent components. We account for the nonadiabatic nature of solar oscillations by including the perturbations of the radiative energy…
Precession from Hipparcos and FK5 proper motions compared with current values: Reasons for discrepancies
Walter, H. G.; Hering, R.
The comparison of Hipparcos and FK5 proper motions points to an inconsistency with the correction, Δ p, of the luni-solar precession derived from VLBI and LLR observations with unprecedented accuracy. An attempt is made to explain this inconsistency of approximately -1.3 mas/yr by rotational offsets of the Hipparcos and FK5 proper motion systems. …
Determination of the Mass Loss Rate and the Terminal Velocity of Stellar Winds. I. Genetic Algorithm for Automatic Line Profile Fitting
Georgiev, L.; Hernández, X.
A new method for automatic fitting of Pline profiles in UV spectra of stellar winds is presented. The line source function is calculated using Sobolev's approximation and the emergent flux is obtained by exact integration of the equation of the radiation transport (similar to the SEI method described by Lamers et al. (1987)). The quality of the fi…
Global observations of energetic electrons around the time of a substorm on 27 August 2001
Davies, J. A.; Baker, D. N.; Li, X. +2 more
The magnetospheric substorm that occurred shortly after 04:00 UT on 27 August 2001 has been a topic of detailed study (Baker et al., 2002; Li et al., 2003). These studies included analysis of data from energetic electron detectors aboard the Cluster and Polar spacecraft that were located in the magnetotail during the substorm. Serendipitously, Cha…
Wavelength and decay length of density overshoot structure in supercritical, collisionless bow shocks
Bale, S. D.; Horbury, T. S.; Saxena, R.
Above some critical Mach number, quasiperpendicular collisionless shocks are known to exhibit ``overshoot'' and ``undershoot'' structure thought to be associated with the motion of ions trapped at the shock front. Using spacecraft potential data from the Cluster spacecraft, the overshoot/undershoot density structure at 56 crossings of the quasiper…
Cluster magnetotail observations of a tailward-travelling plasmoid at substorm expansion phase onset and field aligned currents in the plasma sheet boundary layer
Davies, J. A.; Wild, J. A.; Fazakerley, A. N. +15 more
We present data from both ground- and space-based instruments for a substorm event which occurred on 5 October 2002, with an expansion phase onset time of 02:50 UT determined from the ground magnetometer data. During this substorm, the Cluster spacecraft were located around 15 RE downtail, 8 RE from midnight in the pre-midnig…
Comets, Asteroids and Zodiacal Light as Seen by Iso
Ábrahám, Péter; Müller, Thomas G.; Crovisier, Jacques
ISO performed a large variety of observing programmes on comets, asteroids and zodiacal light covering about 1% of the archived observations with a surprisingly rewarding scientific return. Outstanding results were related to the exceptionally bright comet Hale Bopp and to ISO's capability to study in detail the water spectrum in a direct way. But…
Global structure and composition of the martian atmosphere with SPICAM on Mars express
Bertaux, Jean-Loup; Dimarellis, E.; Forget, F. +26 more
SPectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars (SPICAM) Light, a light-weight (4.7 kg) UV-IR instrument to be flown on Mars Express orbiter, is dedicated to the study of the atmosphere and ionosphere of Mars. A UV spectrometer (118-320 nm, resolution 0.8 nm) is dedicated to nadir viewing, limb viewing and verti…
An ISO-LWS two-colour diagram of Herbig Ae/Be stars
Elia, Davide; Strafella, Francesco; Campeggio, Loretta +2 more
In this paper, we present and discuss an infrared two-colour diagram built with the 60, 100, and 170 µm photometry of the whole sample of Herbig Ae/Be stars observed by the spectrometers on board of ISO satellite. An overview of this diagram reveals a certain degree of homogeneity in the behaviour of these stars and their IR-emitting environ…
The Cool Interstellar Medium
Miville-Deschênes, Marc-Antoine; Verstraete, Laurent; Abergel, Alain +2 more
Infrared spectroscopy and photometry with ISO covering most of the emission range of the interstellar medium has led to important progress in the understanding of the physics and chemistry of the gas, the nature and evolution of the dust grains and also the coupling between the gas and the grains. We review here the ISO results on the cool and low…