Search Publications
Ultraviolet Observations of Three Classical Novae during Early Stages of Decline
Drechsel, H.; Rahe, J.; Wargau, W.
We present IUE UV spectra of the three recent classical novae N Sgr 1982, N Ser 1983, and N Mus 1983, obtained during early decline, transitional stage, and nebular phase, respectively. The line spectra are discussed. Preliminary conclusions concerning CNO over-abundances, shell geometry, and speed classes are drawn.
IUE detector saturation and the new 2800 Å absorption featre `discovered' by Karim, Hoyle, and Wickramasinghe
Savage, B. D.; Sitko, M. L.
The broad λ2800 Å absorption feature 'discovered' by Karim, Hoyle, and Wickramasingle is instrumental in origin. The feature is produced by IUE detector saturation effects in overexposed spectra.
Observations of Binaries and Evolutionary Implications
De Loore, C.
Comparison of the characteristics of groups of stars in various evolutionary phases and the study of individual systems allow to make estimates of the parameters governing mass loss and mass transfer. Observations enable us in a few cases to determine geometric models for binaries during or after the mass transfer phase (disks, rings, common envel…
On the λ 2800 Å interstellar extinction feature
Wickramasinghe, N. C.; Karim, L. M.; Hoyle, F.
We answer our critics and confirm the reality of a feature in the interstellar extinction curve near λ 2800 Å for stars showing abnormally low graphite absorption.
Radial velocity and profile variations of the ultraviolet circumstellar lines in ζ tauri
Hirata, R.; Dawanas, D. N.
The radial velocity and profile variations of UV lines of the shell star ζ Tau have been examined in the IUE spectra obtained in 1978–1982. The neutral atoms, and once or twice-ionized ions (exceptCII, AlIII, SiIII resonance lines) follow the same velocity variations as in the visual spectra, while the SiIV andCIV resonance lines show a constant n…
Spectroscopic Segregation in Binary Systems
Darius, J.
Binary systems displaying spectroscopic segregation, whereby line spectra of the two components overlap little or not at all in wavelength, account for a small subset of LUV objects (late-type ultraviolet). Optical and ultraviolet (IUE) spectra for one such system, HD 15351+UV0225+13 (F4-5 V+sdO), are presented and a few related systems described.…
Variations of UV chromospheric emissions during a pulsation period ofϱ Puppis (HD 67523)
Fracassini, M.; Pasinetti, L. E.; Castelli, F. +2 more
The peculiar δ Del-variable ϱ Puppis (F6IIp) has been analysed on nine UV high-resolution spectra in the region of MgII h- and k-lines. This analysis has shown: (1) The MgII emission is present during the whole pulsation period and increases with increasing luminosity. Maximum emission fluxes seem to occur at phases 0.96–0.12. (2) The phase shift …
Interstellar proteins and the discovery of a new absorption feature at λ=2800 Å
Wickramasinghe, N. C.; Karim, L. M.; Hoyle, F.
The discovery of a broad interstellar absorption feature centred on λ2800 Å in the extinction curve of starlight confirms the presence of proteinaceous material in grains.
The Age Decay of Stellar Magnetic Activity in MS Field Solar Type Stars
Vazquez, M.; Cabestany, J.
The age decay of two indicators of the stellar magnetic activity (λ 2800 MgII emission flux and λ 10830 HeI equivalent width) have been studied for field solar-type stars. The Li abundance has been used, in most of the cases, as a stellar age indicator. A calibrated decay law for MgII has been determined and compared with a similar one, recently p…
IUE observations of certain short period RS CVn-like stars
Budding, E.; Gimenez, A.; Kadouri, T. H.
Nine low and one high resolution IUE (LWR) spectrograms for the short period subgroup RS CVn-like stars have been studied, particularly in connection with the MgII 2800 Å feature. Clear emission contributions can be easily seen for some of these stars, while all nine of them appear to have the feature filled by emission to some extent. If surface …