Search Publications
The heavy ion analyser PICCA for the Comet Halley fly-by with Giotto
Anderson, K. A.; Reme, H.; Korth, A. +12 more
The heavy ion analyzer RPA2-PICCA is designed to identify the composition and distribution of thermal positive ions in the coma of the comet Halley. The instrument is an electrostatic analyzer which takes advantage of the large relative flyby velocity and the fact that the ions in the inner coma should have low temperatures and be predominantly si…
Sulphur compounds in cometary IUE spectra
Krishna Swamy, K. S.; Wallis, M. K.
Bands of S2 have been identified in several comets including Černis, Bowell, Churyumov-Gerasimenko, Encke, etc., covering a wide range in heliocentric distances. S2 seems to have been present in comet Halley even from 1985 early December when it was at 1.5 AU. The authors have also tentatively identified bands of the B-X syst…
The ultraviolet spectrum of the peculiar emission-line star GG Carinae.
Gosset, E.; Swings, J. -P.; Brandi, E.
This paper presents the first study of the properties of the peculiar emission-line star GG Carinae in the ultraviolet wavelength domain. From IUE high resolution spectra, the authors investigate the behaviour of different velocities. From IUE low resolution data, they propose a value of the B-V excess of EB-V = 0.52±0.04 (2σ). The cont…
Low-Energy X-Ray Observations of the Wolf 630 System
Johnson, Hugh M.
The septuplet of M dwarfs is resolved into three components, Wolf 630ABab, Wolf 629ab, and VB 8AB, with the EXOSAT channel multiplier array (CMA). W 630 and VB 8 have previously been observed with the Einstein high resolution imager (HRI). The ratio of CMA to HRI count rates for VB 8 can be produced with an isothermal plasma model temperature T = …
IUE observations of the broad continuum feature at 1400 A in the silicon and related stars.
Shore, S. N.; Brown, D. N.
The upper main sequence chemically peculiar stars have previously been studied spectrophotometrically using low resolution TD-1 spectra. These show that the broad continuum feature at 1400 Å is a useful indicator of Si anomaly. In this paper the authors extend this to IUE low resolution spectra and show that this feature is indeed well correlated …
EXOSAT observations of the ring nebula NGC 6888 and HD 192163
Kaehler, H.; Ule, T.; Wendker, H. J.
A 25 hr exposure of the ring nebula NGC 6888 was obtained with the EXOSAT X-ray Observatory. X-ray emission of the nebula was not found. Taking all instrumental effects and the large nebular area into account, a conservative upper limit of 1×10‑12 erg s‑1 cm‑2 (0.05–2 keV) is derived. This is about an order of magn…
Physical parameters for Population II stars.
Cacciari, C.; Morossi, C.; Malagnini, M. L. +1 more
The observed energy distributions from the ultraviolet to the near-infrared for a number of Population II stars have been collected from the literature (Christensen, 1978; Cacciari, 1985) and have been compared with the Kurucz (1979) model atmospheres computed for different [M/H] ratios. Effective temperatures, surface gravities and apparent angul…
Spectral features of the B2e star EW Lac before and during the variable shell phase.
Floquet, M.; Hubert, A. M.; Chauville, J. +1 more
An examination of the spectral characteristics of the B2e shell star EW Lac before and during the variable shell phase is presented based on 93 spectrograms obtained between 1960 and 1984 with the Haute Provence Observatory coude spectrograph. Characteristics of the prevariable shell phase include radial velocity fluctuations of shell lines of wea…
Some diatomic molecules from comet P/Halley's UV spectra near spacecraft flybys
Krishna Swamy, K. S.; Wallis, Max K.
The abundances of diatomic molecules seen in the UV both give clues to the parent compounds and help unravel the gas and ion mass spectrometry. From IUE spectra of comet Halley, the authors find upper limits on SH and CS+ column densities, and estimates of probable NO, S2, and SO. In particular, judged from the 226 nm γ-band,…
Atmospheric Eclipses in the SMC Wolf-Rayet Eclipsing Binary HD 5980: The Heavy versus the Light Metal Abundance
Koenigsberger, G.; Auer, L. H.; Moffat, A. F. J.
Phase-dependent variations in the IUE spectra of the SMC 19.6-day eclipsing binary system HD 5980 (WN4 + 07I) are discussed. The effects of selective atmospheric eclipses in the N, C, and He lines of HD 5980 are found to be similar to those observed in its Galactic counterpart, while the variations in the 1350-1490 A continuum region are virtually…