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Early observations of Supernova 1987A with the International Ultraviolet Explorer (IUE).
Panagia, N.; Talavera, A.; Clavel, J. +7 more
Early phase observations of the SN 1987A in the ultraviolet wavelength range are presented. Some general considerations on the behaviour of this supernova are given. Also, a comparison is made with other supernovae observed in the ultraviolet with the IUE Observatory.
EXO 023432-5232.3 : a new 114-minute probable AM Herculis-type binary.
Tagliaferri, G.; Beuermann, K.; Giommi, P. +1 more
A new probable AM Herculis binary was found in the course of an optical identification program of serendipitous X-ray sources detected with the EXOSAT satellite. Spectrophotometry of the 19 mag optical counterpart shows that it carries most of the hallmarks of AM Herculis binaries. The orbital period is 114.6 minutes and makes it the sixth AM Her …
Description of the Main Boundaries Seen by the Giotto Electron Experiment Inside Comet p/ Halley - Solar Wind Interaction Region
Anderson, K. A.; Reme, H.; Korth, A. +8 more
The Giotto electron-plasma experiment identified several boundaries inside the comet Halley-solar wind region. Two of them are particularly interesting; they separate very different plasma regimes on quite sharp length scales and furthermore their existence was not foreseen in theoretical models. They are the limit between the transition region an…
The composition and radial dependence of cometary ions in the coma of comet P/Halley
Anderson, K. A.; Korth, A.; Carlson, C. W. +2 more
The heavy ion analyzer, RPA2-PICCA, on board the Giotto spacecraft detected an increase in the densities of cometary ions within a cometocentric distance of 150,000 km. The composition of cometary ions changed dramatically as the comet's nucleus was approached, but it was clearly dominated by the water group. The second and third most abundant ion…
Non-LTE abundance analysis of the early-type high galactic latitude star HD 100340.
Dufton, P. L.; Lennon, D. J.; Keenan, F. P. +2 more
Stellar equivalent widths and line profiles, measured from high resolution AAT and IUE spectra, are used in conjunction with non-LTE and LTE model atmosphere calculations to estimate the atmospheric parameters and chemical composition of the early-type high galactic latitude star HD 100340. The effective temperature (Teff= 25000K), surf…
EXOSAT observations of the 1983 outburst of the rapid burster : a newmode of behaviour.
Haberl, F.; Stella, L.; Parmar, A. N. +4 more
The results of three observations of the rapid burster (MXB 1730-335) made in August 1983 are reported. A new mode of behavior consisting of strong persistent emission at a level of about 5 microJY along with type I bursts recurring approximately every 80 minutes, is reported. No type II bursts were seen during this interval. The spectrum of the p…
The interpretation of the UV light of elliptical galaxies.
Kjaergaard, P.
The UV spectra of the dwarf elliptical M 32 and the two Virgo giant ellipticals NGC 4472 and NGC 4649 are discussed using the spectrum synthesis technique in the whole wavelength region from 1500 A to 2.3 microns. For M 32, the UV spectrum may be explained in terms of evolved blue stars from a minor metal-poor component together with a small contr…
The diffusion of gallium in main-sequence peculiar stars.
Artru, M. -C.; Alecian, G.
New observations of the gallium abundance in main-sequence peculiar stars are now available in the literature. The present paper analyses these new data in the framework of the diffusion processes. The radiative accelerations of gallium are computed, with up-to-date gallium line data, in various physical conditions of stable main-sequence star atm…
Fine dust structures in the emission of comet P/Halley observed by the Halley Multicolour Camera on board Giotto
Keller, H. U.; Thomas, N.
Halley Multicolor Camera (HMC) observations on board the ESA Giotto spacecraft provided images of comet P/Halley with resolution 4-orders of magnitude better than from the ground in March 1986. The fine structure seen in the emission from the cometary surface has led to some confusion over the nomenclature of jets and jet-like features streaming f…
Giotto / IMS Observations of Ion Flow Velocities and Temperatures Outside the Magnetic Cavity of Comet p/ Halley
Schwenn, R.; Balsiger, H.; Goldstein, B. E. +8 more
Fluid parameters for He2+ ions obtained from the Giotto Ion Mass Spectrometer HERS sensor are presented; also investigated are proton densities and velocities and thermal speeds of protons, alpha particles, and heavy ions in the hour before closest approach. A bow shock transition lasting ten minutes is observed. A region of enhanced He…