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New results from Exosat

Fabian, A. C.

VIRIS-VAX interactive reduction of IUE spectra.

Desko, R. D.; Bord, D. J.; Davidson, J. P.

A set of computer programs, VIRIS, which has been developed to aid in the reduction of IUE spectroscopic data is described. Various methods of filtering and smoothing the IUE data are discussed, and spectral rectification routines are described. Routines which automatically locate and store the positions of absorption lines are described, as are r…

Stellar Wind from the Nucleus of the Nebulae YM:29

Lozinskaya, T. A.; Arkhipova, V. P.; Moskalenko, E. I.

Comet plasma tail formation - Giotto observations

Winningham, J. D.; Thomsen, M.; Borg, H. +8 more

The process of mass loading of the solar wind by cometary ions, which forms comet tails, has been observed throughout the coma of comet Halley. Three distinct regimes were found where the nature of the energy and momentum coupling between solar wind and cometary ions is different. Outside the bow shock, where there is little angular scattering of …

Extraterrestrial material analysis: Achievements and future opportunities for laboratory analysis in NASA and ESA planetary programmes

McDonnell, J. A. M.

Achievements in the understanding of the nature and distribution of extraterrestrial material recovered from space missions and stratospheric collection of ``Brownlee particles'' are examined in the context of the analytical techniques which have been applied to their study. A very wide range of powerful tools and techniques is now available for t…

The Giotto encounter with Halley's Comet - First scientific results

Reinhard, R.

The Giotto spacecraft passed within 600 km of the Comet Halley nucleus on the sunward side. Dust jets which form spirals around it while the nucleus rotates once every 52-53 hr caused the collision of large dust particles with Giotto starting 15 sec from closest encounter. A nutation induced on the spacecraft by the impacts were damped by on-board…

Upper limits to ultraviolet line emission in fully convective M-dwarfs

Moreno, H.; Ambruster, C. W.; Kunkel, W. E. +1 more

Theoretical stellar structure models find that stars later than ~dM3 are fully convective. It is widely believed that this should result in reduced non-radiative heating and activity levels, however, the observational evidence is sparse and somewhat contradictory. In order to expand the number of atmospheric diagnostics for these stars, we have ob…

Simultaneous X-Ray and Photometric Observations of the Flare Star YZ CMi

Doyle, J. G.; Butler, C. J.

Broad-band photometric observations of YZ CMi show a 1.2 magnitude U-band flare, however, simultaneous X-ray observations from EXOSAT show no detectable increase. It is suggested that the energy was dissipated before reaching the corona. Two long duration U-band enhancements detected during the optical monitoring may have been the result of back-h…

Detection of an X-Ray Flare from a Single G Dwarf Star

Piro, L.; Monsignori-Fossi, B. C.; Landini, M. +1 more

About the Absolute UV Flux of the OF Star HD 152408

Petrov, P.; Hua, Chong Trung; Magnan, A. +2 more

The UV telescope with a three channel spectrometer was launched on March 23, 1983. The absolute calibration of the system was carried out using standard stars measured by the TD1 and IUE spacecrafts. During the first months of operation, photometric controls were done in order to test the stability, reproducibility of the data. These measurements …