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The UV variations of the symbiotic star CH Cygni from 1978 to 1981.
Hack, M.; Persic, M.; Selvelli, P. L.
The spectroscopic changes of CH Cygni from early 1978 to late 1981 are discussed with reference to several ultraviolet spectra obtained at the Villafranca Satellite Tracking Station. Correlations have been found to exist between the fluxes of the continuum and the fluxes of the forbidden and semiforbidden lines. Three new forbidden-line identifica…
Evolution of the ultraviolet coma of comet Austin (1982g.)
Feldman, P. D.; Keller, H. U.; A'Hearn, M. F. +6 more
Ultraviolet spectra of comet Austin (1982) obtained in July 1982 at heliocentric distances ranging from 1.10 to 0.81 AU preperihelion with the IUE reveal that the comet is very similar in chemical composition and appearance to comet Bradfield (1979X). In addition, the derived H2O production rate is found to vary with heliocentric distance as r to …
Far-ultraviolet spectra of the nuclei of globular clusters M 30, M 54, M 70.
Wamsteker, W.; Caloi, V.; Castellani, V. +1 more
IUE spectra in the low dispersion mode have been collected from the nuclei of the three galactic globular clusters NGC 6681 (= M70), NGC 6715 (= M54), and NGC 7099 (= M30). High UV fluxes are obtained from M54 which had been found earlier to be a real characteristic of the cluster population, suggesting a possible connection of this cluster with E…
Discovery of a white dwarf companion of the "hybrid" K giant HD 81817.
Reimers, D.
IUE observations show that the bright K giant HD 81817 has a faint blue companion which is identified as a white dwarf. A fit of theoretical DA model atmosphere fluxes to the observed energy distribution in the wavelength range λλ1250 Å to 1600 Å yields an effective temperature Te = 20000±2000K for the WD companion and places the WD at …
The masses of early-type stars in the galactic halo determined from ultraviolet resonance line profiles.
Dufton, P. L.; Keenan, F. P.
Terminal velocities for stellar winds in intermediate and high galactic latitude OB stars have been determined from high resolution IUE ultraviolet spectra. These velocities, together with previous estimates, have been used to deduce stellar masses which are found to be similar to those derived from conservative and non-conservative evolutionary t…
Simultaneous IUE and ground-based observations of V923 Aquilae.
Ringuelet, A. E.; Rovira, M.; Sahade, J. +2 more
Simultaneous IUE and ground-based observations of V 923 Aquilae carried out in July 1981 are used to propose a model of the extended envelope of this Be star with a transition region relatively close to the star, where the highly ionized species would be formed. The shell photographic and ultraviolet lines of Fe II and the photographic lines of Ca…
The IUE blaze function in the MG II region.
Morossi, C.; Vladilo, G.; Allocchio, C.
To obtain reliable emission profiles of Mg II resonance lines from the IUE data it is absolutely necessary to perform a good ripple correction of the IUE net spectrum. An experimental blaze function (valid for the IUE orders from 88 to 79) has been derived as the ratio between the IUE data and those of the Copernicus satellite: in fact, the latter…
A comparison between various UV photometric systems for late-type stars.
Cacciari, C.; Wamsteker, W.; Norgaard-Nielsen, H. U. +1 more
Ultraviolet absolute photometry and spectrophotometry obtained for late-type stars with the TD1, OAO-2, ANS, and IUE satellites are compared. Strong colour effects are found in the TD1 2740 Å band, and, to a lesser extend, in the OAO-2 2980 Å band. The reason for these effects is believed to be due to red leaks in the sensitivity functions. For th…
Ultraviolet spectrophotometry of isolated galaxies.
Brosch, N.; Greenberg, J. M.; Rahe, J. +1 more
The authors have obtained ultraviolet spectrophotometry of five isolated galaxies with the IUE which confirms the existence of the ultraviolet excesses first found by UBV photometry. Observations from the optical part of the spectrum to the radio bands are combined with the ultraviolet data to explain the nature of the UV excesses as the signature…
The transition layer of eleven late-type stars.
Montesinos, B.; Rego, M.; Fernandez-Figueroa, M. J.
Far UV-spectra of eleven F, G, and K stars of different luminosity class have been studied. Si IV, C IV, and N V emission line fluxes have been used to obtain parameters for the transition region. The stars of the sample have been classified according to the activity level. Using two abundance criteria the gaseous pressure upper limits have been c…