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The remarkable Herbig AE star V 351 Orionis=HD 38238.
The, P. S.; de Winter, D.; van den Ancker, M. E.
The photometric behaviour of the irregular variable Herbig Ae star V 351 Ori was investigated combining data from the literature with new photometric data in the Stroemgren system. It is shown that this enigmatic object changed its photometric behaviour from that of a Herbig Ae star with strong photometric variations, due to extinction by circumst…
The central star of the planetary nebula NGC 6302.
Pottasch, S. R.; Beintema, D.; Vandenbussche, B. +3 more
Selected results from the ISO spectrum of NGC 6302 are reported. The intensity of the high ionization [Mg VIII] line is given. The controversy concerning the mechanism of ionization of the high ionization stages, and especially the [NeV] lines is discussed. It is concluded that all lines can be reproduced in a photoionization model, if the tempera…
Very cold dust associated with molecular gas.
Prusti, T.; Burgdorf, M.; Laureijs, R. J. +4 more
We report the detection of very cold dust in a small and isolated dust cloud. Observations at 60, 90, 135, and 200µm show a constant surface brightness ratio I_135_/I_200_ and a flattening of I_90_/I_200_ towards the cloud centre. The dust temperature derived from the far-infrared colours can be confined to the range of 12-15K assuming a λ^-…
Time and space variations of the Galactic cosmic ray electron spectrum in the 3-D heliosphere explored by Ulysses.
Sierks, H.; Kunow, H.; Wibberenz, G. +7 more
The Ulysses spacecraft, launched in Oct. 90 after solar maximum of solar cycle 22, has explored the heliographic latitudes above 70degS in summer 94, and has then made a rapid latitude scan down to the heliographic equator reached in March 95, in a period close to solar minimum. We present hereafter the Galactic electron spectra, with energies abo…
A search for hot post-AGB stars in the IRAS Point Source Catalog.
Oudmaijer, R. D.
In this paper a first step is made to search for hot post-AGB stars in the IRAS Point Source Catalog. In order to find objects that evolved off the AGB a longer time ago than post-AGB objects discussed in the literature, objects that were not detected at 12 µm by IRAS were selected, The selection yielded 15 objects, of which 12 have spectral…
ULYSSES out-of-ecliptic observations of interplanetary shocks.
Balogh, A.; Forsyth, R. J.; Burton, M. E. +4 more
Interplanetary shocks observed at the Ulysses spacecraft as it traveled from the ecliptic plane to the southern solar pole have been identified and analyzed using both magnetic field and plasma measurements. The latitude dependences of various parameters associated with the shocks (beta, θ_BN_ and Mach number) have been investigated. The direction…
The central stars of the planetary nebulae NGC 7027 and NGC 6543.
Waters, L. B. F. M.; Pottasch, S. R.; Beintema, D. A. +6 more
Infrared spectra of NGC 7027 and NGC 6543 ranging from 2.4 to 45µm were obtained with the Short Wavelength Spectrometer on board the Infrared Space Observatory. A first analysis of these spectra, with the aid of photo-ionization models, is presented. We report the first detection of the [ArVI] 4.53µm and [NeVI] 7.65µm lines in th…
HD 133656: a new high-latitude supergiant.
Trams, N. R.; Van Winckel, H.; Oudmaijer, R. D.
In the course of our study of post-Asymptotic Giant Branch objects, we discovered that the seventh magnitude A supergiant HD 133656 has an infrared excess emission due to cool circumstellar dust, and that its photospheric abundance pattern is population II like. We present a detailed abundance study of the object, and discuss its nature in terms o…
The empirical white dwarf mass-radius relation and its possible improvement by HIPPARCOS
Schmidt, H.
The famous mass-radius relation of white dwarf stars is based on theoretical considerations. The structure of a white dwarf, and thereby its fundamental properties, are deduced from the physical properties of the degenerate electron gas. Numerical computations take temperature and evolution effects into consideration. However, the few cases in whi…
CIV absorption from hot gas inside the supergiant shell LMC4 observed with HST and IUE.
Bomans, D. J.; de Boer, K. S.; Grebel, E. K. +1 more
High resolution ultraviolet spectra obtained with the HST-GHRS of two stars in the direction of the supergiant shell LMC4 unambiguously show absorption by substantial quantities of CIV gas at velocities near the the systemic velocity of the LMC. In combination with the detection of diffuse X-rays from the LMC4 by ROSAT and other supporting data, t…