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The microwave sensing in the Cassini Mission : the radar

Johnson, W. T. K.; Borgarelli, L.; Im, E. +1 more

The spacecraft of Cassini Mission has been launched towards Saturn on October 1997 to study the physical structure and chemical composition of Saturn as well as all its moons. To this end many instruments have been mounted on the spacecraft ; one of these is the Cassini Radar. Cassini Mission is a cooperative mission between NASA (National Aeronau…

The Hipparcos satellite: a dramatic improvement in our knowledge of the solar neighbourhood.

Turon, C.

Hipparcos was the first satellite to accurately measure angular displacements on the sky. Thanks to its original design, positions, trigonometric parallaxes and proper motions of unprecedented accuracy have been obtained for about 118000 stars and 50 objects in the solar system. The results cover a wide variety of subjects: reference systems, stel…

AGB Stars in the Magellanic Clouds

Groenewegen, M. A. T.

Some recent results on AGB research in the Magellanic Clouds are reviewed. Discussed are optical and IRAS based surveys, and recent results from the near-infrared DENIS survey, and ISO observations.

Hydrodynamical Modelling of the Evolution of Dusty Outflows from AGB-Stars

Steffen, M.; Szczerba, R.; Schönberner, D.

The Structure of the Local Hot Bubble Toward L = 165^o, B = 0^o Using IUE and ROSAT Data

de Boer, K. S.; Kerp, J.

The first X-ray-opaque cloud in the direction of Auriga lies at 180 pc. A tenuous cloud, whose distance is derived from IUE absorption line studies as well as from an analysis of ROSAT data, is embedded at 55 pc. The X-ray emitting gas has a temperature of 10^{5.9-6.0} K. The pressure is 1.6 10^4 K cm^{-3}.

Minor planets ephemerides improvement. From joint analysis of HIPPARCOS and ground-based observations

Hestroffer, D.; Viateau, B.; Rapaport, M.

Two methods are considered for the improvement of the ephemerides of the asteroids observed by the Hipparcos satellite. They utilize different combinations of ground-based and space-based data. In particular, we develop a method based on an analysis of the variance matrix in the least-squares solution of Hipparcos observations taken alone. Applica…

Infrared Astrophysics in the Space with ISO From ISO to FIRST

Cernicharo, J.

I present some of the results we have obtained with the four instruments on board of the ISO satellite. The determination of water vapour abundance, the study of star forming regions and the determination of the physical and chemical conditions in evolved stars are discussed. The implication of these results for future space-based observatories li…

Parallaxes and Proper Motions of Prototypes of Astrophysically Interesting Classes of Stars

Kundu, Arunav; Trimble, Virginia

Hipparcos data are presented for 13 stars belonging to six different evolutionary types that present various puzzles. There are three FK Comae stars, one Wolf-Rayet binary, the ``galloping giant'' FG Sagittae, two high-velocity B stars, two runaway T Tauri stars, and four cataclysmic variables. Most of the numbers are of limited statistical signif…

ISO-LWS Observations of the NGC7129 Star Forming Region

Giannini, Teresa; Nisini, Brunella; Lorenzetti, Dario +2 more

We present far-infrared observations of the surroundings of the Herbig Be star LkHα234 in NGC7129, obtained with the Long Wavelength Spectrometer on board of the Infrared Space Observatory. [CII]158µm, [OI]63µm and [OI]146µm lines are detected everywhere in the mapped region and their intensity ratios are consistent with the model predictions of a…

Energetic solar particle dropouts detected by Ulysses at 1.63 AU: A possible encounter with the Earth's distant magnetotail

Phillips, John L.; Lin, Robert P.; Ashford, Stephen M. +2 more

Fast solar particles are used to trace the topology of the interplanetary magnetic field during a solar event detected by the heliosphere instrument for spectra composition and anisotropy at low energy (HISCALE) on the Ulysses spacecraft on January 2, 1991. Two sharp-edged dropouts, lasting for 10 and 25 min, were detected in the fluxes of solar i…